


A Kind of Merry War

by blithers



Category: Life with Derek
Genre: Arguing, Bets & Wagers, Coming In Pants, Drinking Games, F/M, Inappropriate Erections, Making Out, Strip Poker, Underage Drinking
Language: English
Status: Completed
Published: 2014-06-07
Updated: 2016-08-02
Packaged: 2018-02-03 18:24:31
Rating: Mature
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 7
Words: 37,181
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/1754063
Author URL: https://archiveofourown.org/users/blithers/pseuds/blithers
Summary: <blockquote class="userstuff">
              <p>Three games that Derek and Casey played.</p>
            </blockquote>





	1. Twister

**Author's Note:**

> Set sometime late season 3/early season 4-ish. Thank you so much to jaegermighty/moirariordan for the beta!

It starts, as most things do, with being Derek being a total jerk.

“But mooooooooom," she whines, “Emily and I need the Prince on Friday! We just got invited to -“

“Bor-ing,” Derek announces, shoveling pancakes haphazardly into his mouth.

“You know Derek has the car this Friday,” her mom replies without looking at either of them, digging around in the junk drawer by the phone for the permission slip Lizzie had yelled at all of them about this morning, although Casey still wasn’t sure why _she’d_ been caught in the crossfire. Like she’d lose a permission slip.

“All mine,” Derek agrees gleefully through a mouthful of food, because he’s basically a two year old with a height problem.

Casey stares at him resentfully. “What do you need the car for, anyway?”

“Sam and I are roadtripping to Kincardine after school.”

“What? _Why_?”

Derek gazes nobly off into the distance. “Why did man go to the moon, Casey? Because it’s _there_.”

“Oh. My _god_.”

He shoves another gigantic forkful of pancake into his mouth and shrugs. “We don’t have a game this week. What else are we supposed to do?”

Casey turns to face Nora again. “Seriously, mom?”

Nora pushes her hair back out of her face and starts in on the stack of papers wedged behind the phone on the wall. “It’s not my car, Casey.”

“But…”

“Casey, if Derek wants to trade a day with you, that’s fine, but you know this is something you two need to sort out between yourselves.”

Casey crosses her arms over her chest and Derek grins widely at her, flashing a jack o’lantern mouth full of mashed-pancake-and-syrup teeth.

—

She hunts Derek down after third period.

“I’ll trade you for the Prince,” she says. “All next weekend for this Friday.”

Derek purses his lips together and acts like he’s considering her offer for .5 seconds before shaking his head with exaggerated regret. “No go, Case.”

“But -“

“Nope.”

“You -“

“You’ll have to do better than that,” he says, and walks away whistling.

—

“I’ll do your chores for the week,” she says after fifth period, gritting her teeth. That makes Derek pause. He makes this big, dumb production out of mulling over her question like he doesn’t already know exactly what he’s going to say before slamming his locker shut.

“Nah,” he says finally. “Not good enough.”

She grips her textbooks tighter and rolls her eyes as obviously as possible. “Just tell me what you want, Derek.”

“Walk with me, Casey,” he says grandly, and throws an arm over her shoulders.

“What are you -“

He steers the the two of them down the hallway, deftly avoiding various cliques and clusters of students. “It’s your lucky day. It just so happens you do have something I want.”

“Wow,” she says sarcastically.

“I know.”

“Spill.”

“It may have come to your attention that I have a book report due next Friday. In fact, I have a couple of book reports due over the rest of the semester and sadly, Caseface, none of them are available as movies.”

“You’ve got to be kidding me.”

“I know. I mean, how good can a book be if nobody’s made it into a movie yet?”

“You want me to write a book report for you?”

“I want you to write _all_ of my book reports for me,” he clarifies. She tries to shake his arm off, annoyed, but he tightens his grip and leans in closer to her.

“No way.”

“No Prince, no party, no,” his voice turns high and sickeningly sweet in her ear, “ _you know who_.”

“Okay,” she says slowly, and turns to face him as much as she can. “Fine. I’ll do it. _If_ I get the Prince for the entire month.”

He barks a short, sharp laugh. “Funny, Casey.”

“That’s my final offer.”

He looks down at her, his mouth tugging back and forth between a frown and a oddly level stare, before saying, “Can’t swing it, Case.”

She lifts an eyebrow and smiles up at him sweetly. “Well, isn’t that interesting.”

—

“I have a proposal.” Derek throws his hockey bag on the kitchen table, knocking over a teetering pile of depositions George had forgotten that morning and a half-finished science fair project. “We bet on it. You and me, Casey, we settle this mano-a-mano.”

Casey grabs a half-painted styrofoam Jupiter making a desperate bid for freedom at the edge of the table. “I think you mean mano-a-womano.”

“Sure, whatever. I’m saying we make this interesting: a game of chance, winner takes all. I win, you write my book reports. You win, you get the Prince for a month.”

“What’s the catch?”

“No catch.”

She narrows her eyes. “I don’t believe it. You’ll cheat, and you know it.”

“I would never…!” He slaps a palm over his heart and adopts a wounded expression. “Okay, yeah, totally. But I’d let you cheat too.” His voice turns wheedling, cloyingly charming.

“I’m not going to turn this into a competition about who can cheat better!”

“Only ‘cause you’re scared you’ll lose.”

Like she’d fall for an amateur line like that.

“C’mon, Casey. I’ll even let you pick the game. Anything you want, just name it.”

Now _that_ is more interesting. She considers him carefully, holding Mercury in one hand and a painted Mars in the other. His hair is shaggy like a sheepdog, sticking every which way because he’s been avoiding Nora whenever she mentions getting it cut, and he’s watching her steadily, calmly. Casey licks her lips, then sticks out her hand.

“Fine. You’re on.”

Derek spits on his palm and grabs her hand before she realizes what’s happening and can yank it back. The palm of his hand is wet and viscous as it mashes into her own.

“Eew, _Derek_!” she yells, and tries to wrench her hand out of his, but he tightens his grip. The slimy warmth of his saliva is pressed between their palms, slippery and lukewarm like bathwater, and it is MAJORLY GROSS.

“Blood oath,” he says in this weirdly serious tone, holding tight to her hand. “You can’t back out now, Case.”

“Let go of my hand, Derek!”

“No.”

“One: that is not blood, that is your _spit_ and it is probably the most disgusting thing that’s ever happened to me. Two,” she moves in a step closer to him, and stops trying to tear her hand free of his grasp, “you _wish_ I’d back down. I’m going to chew you up and eat you for breakfast, Derek Venturi.”

“You wish.”

“ _You_ wish!”

“ _You wish_!”

“It’s always so nice to see our two eldest getting along, isn’t it?” George says, unwrapping a scarf from around his neck as he comes in through the back door.

“Did you just say Derek and Casey were getting along again?” Her mom’s head pops up from behind George’s shoulder. “They’re really _too_ well-behaved, don’t you think, George? We should encourage them to rebel a little more.”

“Oh, definitely.”

“Hi, Mom,” Casey says, and waves with her free hand.

Derek grins, wide and unabashed. “Hey, Dad. Kill ‘em at work today?”

“Always, kiddo.”

“Why are Casey and Smerek holding hands?” Marti asks. Casey looks down at their joined hands, and Derek tightens his grip.

“Your big brother’s starting an outreach program to help the less fortunate, Smarti,” Derek says. “You know: looks, smarts, social life. Everything I have that Casey doesn’t.”

“Derek’s afraid of the dark,” Casey says, louder, over top of him. “I keep telling him he can let go of my hand, but poor wittle Derek is just a big old scaredy cat.”

Marti pulls off her knit hat and throws in the red plastic bin for winter outerwear. “I’m not scared of the dark.”

“No you are not,” Nora says, and bops Marti playfully on the nose. Marti jumps back and hisses, flashing her fingernails as claws.

“Sweetheart, don’t you think you’re a little too old to still be a cat?” George asks.

Marti pouts. “You just said I had t’be a nice kitty.”

“That’s right.”

“Derek’s a cat too,” Marti points out. “We’re both cats. Derek’s a _scaredy_ cat.”

“Oh, no no no,” Derek says.

“ _Yes he is_ ,” Casey says at the same time, and shoots Derek a triumphant glance. “You’re so smart for knowing that, Marti.”

Nora hangs up her coat and frowns at the two of them in the kitchen, still locked in mortal hand-to-yucky-squishy-hand combat. “You know, Marti has a good point: why _are_ you two holding hands?” She lays the back of her hand on Casey’s forehead. “Are you feeling okay, Casey?”

Casey readjusts her grip around Derek’s wrist, and their palms slide wetly against each other. “I’m fine, mom.”

Marti tugs on George’s sleeve. “Dad, if I’m a kitty cat and Derek’s a scaredy cat, does that mean Edwin’s a cat too?”

“Yeah, a _pussy_ cat,” Derek says, and sniggers.

“What about you, Daddy?”

George puffs out his chest and half-grins in that cocky way he has, the one that makes him and Derek look so much alike at the strangest times. “Me? I’m a tomcat.“

“Yes you are, honey,” Nora says, and pats George absently on the shoulder on her way to fulfill the venerated Venturi/McDonald family household ritual of staring into the empty, lonely depths of the fridge for a few precious seconds before giving up and ordering a pizza.

“Meow,” George snarls, pulling a silly face down at Marti and imitating her flexed-finger pose from earlier, and she grins happily up at him.

Derek tugs at Casey’s hand, pulling her into the dining room and away from their family. He drops her hand after they’re out of the kitchen, and air hits the rapidly cooling spit on her palm. She wipes it off on her jeans and fumes silently about spit and boys and all the gross, disgusting things that boys do.

“So what’re we doing?” he says, wiping his own hand down his chest, leaving a dark wet smear down the front of his shirt.

And then a brilliant, absolutely _brilliant_ plan occurs to her.

“…Twister.”

A look of something that might be horror flickers across Derek’s face. “What?”

“Twist-er,” she enunciates, trying not to sound _too_ smug.

“Uh, no,” Derek says.

“What?”

“I said no-ooh,” he repeats, mimicking her.

“Did you seriously just get spit all over my hand so you could wimp out on me? What happened to your whole stupid blood oath thing?”

Derek shrugs. “You’re a girl. Doesn’t count.”

“What. The _hell_.” She shoves Derek with the palms of her hands, and he stumbles a step backwards from her, hair falling into his eyes. He glances at the kitchen, but nobody’s watching them - Nora’s on the phone ordering pizza, and George is holding a shrieking and laughing Marti upside-down. Derek sticks his hands in his pockets instead.

“Twister isn’t a real game.”

“You’re just scared you’ll lose.”

His lips thin out. “Am not.”

“Are too.”

“Am not!”

“ _Are_ …!”

“Ham or pepperoni?” Nora asks, sticking her head out of the kitchen with the phone cradled on her shoulder, and they both answer “Pepperoni” at the same time without breaking eye contact.

“Pepperoni,” Nora repeats into the phone as she wanders away again. “No, unanimous vote.”

“ _Are too_ ,” Casey finishes in a whisper, as soon as her mom’s out of earshot again.

Derek doesn’t say anything for a moment, but something canny starts to shift in his expression as he looks at her.

“There are rules,” she adds hastily. “Like… like you can’t do anything weird to make the other person fall down on purpose. No hitting. Or…or tickling, anything like that.”

He rolls his eyes. “Only you could take a game like Twister and make it un-fun.”

“Look, do you agree or not?”

He only hesitates for a moment.

“Okay. You’re on. One game, boring Casey rules, blah blah blah, whatever.”

She mentally fist-pumps.

“Hey, so the pizza should be here in an hour,” Nora says, walking past them to the stairs with Marti holding her hand, where she stops and swivels to face them again. “I’m taking Marti upstairs to help her pick out an outfit for her school recital tomorrow. But seriously, what’s up with you two? You’re both acting really strange.”

“School,” Casey laughs awkwardly, while at the same time Derek stutters, “E-economics?”

Nora blinks. “What?”

“Political… elections?” Derek tries again.

“Seriously, Derek?” Casey says, and stomps away into the kitchen.

“Well, I feel like that didn’t answer my question at all,” Nora says down to Marti, who shrugs back up at her.

—

“You’re in a good mood today,” Emily says, watching Casey curiously,

Casey digs her English textbook out of the stack of books in her locker, then turns to clasp it to her chest and lean dramatically against her locker, smiling beatifically up at the fluorescent lights dotting the ceiling of the hallway. “You know what, Em? I am.”

“Uh, okay. Any particular reason?”

Casey catches sight of Derek across the hallway, the collar of his black leather jacket thumbed upward like a greaser, headphones slung across the back of his neck, mouth sullen. He sees her staring at him and his expression flattens. He doesn’t talk to her as he walks past, but she sees his shoulders stiffen, and then, slowly, purposefully, he smirks at her.

Casey smiles back and slams her locker shut. “Oh,” she says cheerily to Emily, eyes still following the back of Derek’s head down the hallway, “No reason at all.”

—

They meet in the living room (condition #1: neutral territory) at 11:45 PM on Wednesday after everybody else is in bed (condition #2: absolute and total secrecy). Casey glares at Derek while unpacking the battered cardboard box (tactic #1: INTIMIDATION THROUGH EYE CONTACT).

Derek takes off his socks and shoes and sets them aside. She wrinkles her nose.

"Disgusting much, Derek?"

"Always."

Casey does a couple stretches to loosen up (tactic #2: nothing to stand between her and VICTORY) while Derek smooths out the plastic mat on the floor, permanently creased from untold years of storage. Derek doesn't say anything, intent on the smoothing-out job, until he finally stands up with the spinner in his right hand.

"May the best man," Derek grins at her, showing teeth, “…win."

"The best _woman_ will." She nods at the spinner he's holding. "Bring it on."

He flicks the cheap plastic spinner, and it whirls fast.

"Right foot red."

Casey holds eye contact with Derek as she steps out onto the mat. She _has_ this. She can out-limber, out-balance, and out-contort Derek any day of the week. There's no way a guy who once spent a whole month complaining that his coach wanted him to be able to touch his toes is going to win. She has this one in the _bag_.

The Prince is so hers.

—

"Admit it. The Prince is so mine, Derek.”

He snorts. “You wish. Victory is going to be so sweet."

Left hand green. Casey shifts all her weight to her right hand, snakes the left one underneath Derek, and hooks her wrist behind his to take the far green circle.

"Dream on."

"I do have dreams.” He sighs theatrically. “Dreams of you writing my book reports… doing my laundry… shoveling the driveway…”

"I am not doing any chores for you, Derek! That was so not part of the deal."

"Not yet."

“Uh, not even a little bit.”

"Not yet," Derek repeats. Left foot red. He slides a knee out from underneath her and slips it over the back of her calf.

—

"Can't you just --"

“For the last time, I’m not helping you, Derek!”

“Fine. _Fine_. Just don't say I didn't warn you."

Derek threads an arm underneath her, his elbow jammed into one of her armpits, and mutters something Casey can't quite understand under his breath.

"Giving up?" Casey asks, sweetly. There's only one blue circle left on the board now, and even with his upper body pressed hard into her shoulder he doesn't have the reach to put his hand on it.

"Shut up. I’m working on it."

Derek lowers his body a little closer to the mat. He stretches for the blue dot and his fingers connect, and then he straightens both his arms back up with a grunt. He's… he is right underneath her.

Casey goes very still.

"Your spin," Derek says, but his voice is tight and low all of a sudden, and it's totally weird, because she can _feel_ the vibrations of his voice before she hears them, rattling around in the bones and muscle of his torso. His upper body is hooked underneath hers; the inside of her right elbow is brushing the shell of his ear. Derek's no-hugging, no-acting-like-a-normal-human-being policy means they didn't really touch like this - _ever_ \- unless they're fighting over something, the remote or the last scoop of ice cream in the carton.

But. Here they are.

He's looking at the ground and she's staring at the back of his head. She doesn't have a way to tell how Derek feels about their sudden proximity, this whole up-in-each-other's-business business.

“…Case?”

She shakes herself. “Yeah, right. Sorry. My turn." She slides herself a couple inches down his back, her unbound hair falling into Derek's face, and he sputters and spits hair out of his mouth, like the total drama queen he is. Left foot green.

"Eew, gross-a-mundo. Keep your spiderweb hair to yourself, Space Case.”

She grins. “What, you mean like this?” and shakes her loose hair violently in front of his nose.

She feels his body tense underneath her. " _Stop it_."

"Nope! All's fair in…" _Think about what you're saying,_ "…war. All's fair in war."

Derek's silent for a second. "Do you think it would it be weird if I licked your hair right now?" He takes a slow, theatrical sniff of her hair. "Because I'm thinking that would really freak you out. I've got a good feeling about it. Like, a winning-the-game-and-also-having-you-do-my-chores-for-a-month kind of feeling."

She jerks her head back. “You wouldn't dare."

"Try me."

"Such an act would be a violation of our previously agreed-upon rules, and would, ipso facto, make me the winner of this contest."

He shifts his weight to his right hand to hit the spinner. Left hand yellow. "Pretentious keener says ipso-whatso?"

"Are you sure you're the one whose dad is a lawyer?"

"He's your dad too," Derek says, and slides smoothly out from underneath her.

Right foot red.

"…Cat got your tongue, Case?"

"I know George is my dad too," she snaps. It comes out meaner than she expects.

He spins up right foot yellow, sticks his knee behind hers to get to it, and starts to breathe creepily on her neck. He smells… kind of good? She thinks it's a mix of the body wash that stinks up the shower whenever Derek manages to wake up before her and the cologne he'd talked George into buying the last time they went to the mall.

Also, he is _so_ doing it on purpose.

"Stop breathing on me like a creeper, Derek!"

"So you can dish it out but you can't take it, hairball?"

Left foot blue. She shoves a knee underneath Derek's leg.

Right foot yellow. He hip checks her hard enough to rock her, on-purpose, like he's playing hockey or when they wrestle.

"Der- _rek_!”

"Can't take the heat, get out of the kitchen," he says, super smug, like that isn't the absolute dumbest thing he could have said at this moment.

"You are…"

"You don't need to tell me how awesome I am." Left foot green. "Oh the other hand, go for it. I wanna hear this one."

"You wish," she says, and elbows him in the ribs. His breath whooshes out hot against her neck from the impact.

"Okay, so if you do my chores for the month, I'll stop breathing on your neck or whatever."

Casey grits her teeth and reminds herself, for the ten millionth time, that she can't go at him without losing the game. Eyes on the prize, McDonald! "You're forgetting something, Derek. I'm not going to _lose_." Left hand blue.

He blows in the shell of her ear, and the thin hairs on her arms stick up. Cold with little starburst pops of heat prickle under her skin.

"Case," Derek coos, gloatingly, close to her ear, "are you…"

She swings her hair up and over, smacking him in the face with it, and feels a vicious thrill of pleasure when he starts to sputter again.

—

He sulks for a while after that.

“Awww,” she says, and slips a hand beside his, “did somebody hurt li’l Derek’s feelings?”

“Shut up, Casey.”

“Oh, grow a pair,” she says, and regrets it as soon as the words leave her mouth. Why? Why on earth would she say that? To HIM?

Derek’s eyes widen and she feels his body start to shake, his annoyance forgotten, her shoulder pressed up against his ribs.

He’s laughing.

The… the _jerk_!

“Did you seriously just tell me to _grow a pair_?”

“No?” she tries. “I’m pretty sure you imagined that.”

“But grow a pair of _what_?” he continues, like he hadn’t heard her, his tone a mockery of bewildered puzzlement. “Of what, Casey? Casey. Hey, Casey. Say it again. C’mon, do it. I dare you.”

She flicks the spinner and thinks noble thoughts. “No way.” Left foot green. She spiders her way out to the far corner of the mat, her arms and legs stretched out long.

“I double-dog dare you.”

“No.”

“Okay, okay, I see where you’re going with that. _Triple_ -dog. That’s THREE dogs, Casey. You can’t pass up a dare like that.”

“Cut it _out_ , Derek.”

“Sorry, bzzzt, that’s not the action verb we were looking for! Thanks for playing, no consolation prize for losers.”

Right hand red. He puts his hand down next to hers, spread wide, fingertips dimpling the plastic mat. “How do you know what an action verb is, anyway?”

“Mrs. Carter, my grade seven English teacher. She was,” Derek heaves this stupid, giant, melodramatic sigh, “ _so_ hot.”

Gross. Seriously, why does she ever think Derek is going to give her a normal, non-sexist, non-terrible, non-Derek answer to a simple question?

“Sooooooo hot,” he reiterates, just to prove her point. “We’re talking mega hotness here.”

“You are such a _pig_.”

“Oink oink,” he agrees without a trace of remorse, then throws an arm over her shoulders to get to his next move, his forearm a warm weight across the back of her neck. “Hey, did you catch how I called you a loser earlier? Pretty clever, eh?”

“That was not clever! Only you would think that’s clever.”

“You know, I’d say you’re cute when you’re angry, but the first part of that sentence would definitely be a lie.”

Left foot blue. She jams her hip up against his, harder than necessary.

—

Derek’s better at Twister than she gave him credit for. She sneaks a glance at the kitchen clock from underneath an armpit and is somewhat alarmed to realize that it’s after midnight already. Her arms are starting to ache from the strain of holding herself up so long.

“Derek?”

“Yeah?”

“How are you so… not-terrible at this?”

He moves a hand into her field of vision, his shoulder tucked up against her own. “Wasn’t expecting that, huh?”

“Well… yeah. I mean, you are, you know. _Derek_.”

"Some have called me God's gift to the ladies, and this right here, Casey: this is a game you play with the _ladies_.” He over-pronounces the word with relish. Ugh. She can just picture the cocky grin on his face.

“Fantastic,” she says flatly.

“Exactly,” he agrees.

There’s a thumping noise from upstairs after he speaks, and they both freeze. Casey holds her breath, ears cocked upward, trying to hear above the pounding of her heart. When did her heartbeat get so _loud_?

They stay frozen, half-tangled together and eyes wide, until Casey hears a loud snort, which transitions halfway through into a snore - Lizzie, zonked out after double-practice at soccer today, she’d barely managed to keep her eyes open during dinner. Casey’s shoulders slump with relief.

“Just Lizzie.”

“I know,” he says, only a bit quieter. “Your turn.”

She lands on right foot green. It’s going to be a tough move; she’ll need to shift her weight at least partially underneath Derek to make it.

“So heeeeeey,” she tries, going for a super casual, nope-no-stress-here kind of tone, “since you _are_ so awesome at this, would you mind -“

“What goes around comes around,” Derek says pointedly, and doesn’t move an inch.

Right. Great.

Casey pushes herself off sideways, moves her right leg out to the side of Derek’s foot, and straightens her arms again, locking her elbows. The move slots the two of them together in a reverse of their earlier stacked-on-top-of-each-other position, only this time Casey’s the one underneath Derek, the front of his chest pressed up against her back.

Her heart starts to beat faster, thumping nervously against her ribs. Her left leg is folded up underneath her body, splayed outward a bit but holding her weight, but her right ankle is to the outside of Derek’s, her leg pressed up against his thigh.

Casey realizes, with a dawning mix of horror, that she’s ended up with her rear end pressed up against the front of Derek’s crotch.

 _Doggie style_.

The words flash in neon across her mind like a blinking sign, D-O-G-G-I-E S-T-Y-L-E, like that dumb song that was everywhere on the radio for a while that Sam had thought was hilarious. She fervently hopes that Derek hasn’t developed telepathy in the last couple minutes. Because this would be the WORST TIME EVER for Derek to be able to read her mind.

She starts to pray that they both make it out of this situation without ever, _ever_ talking about it again.

"Derek," she whispers.

She can feel his breath against the side of her neck again, and it makes her stomach knot up uncomfortably, her thoughts sliding nervously up against each other in her gut. She doesn’t think he’s doing it to annoy her this time.

“ _Derek_ ," she repeats, a little louder, trying not to sound desperate. "It's your turn."

She hears him suck in a sharp breath. “I know.”

“So…?”

“Just… chill a minute, Case.”

Of all the…! The idea of staying like this, voluntarily, makes her feel like she’s going to hyperventilate, her stomach twisting in on itself in a mess of confusion, a squirming sense of heat seeping between her legs.

“ _No_ ,” she snaps, trying to keep the panic out of her voice. “Go now, or… or… or forfeit the game, Derek. I mean it!”

“I said,” he says, his voice rising and sounding suddenly young, on the edge of cracking like Edwin’s used to, “ _chill_ , okay.“

She rocks back on her heels to reach for the spinner, trying to get this Over With, so they can move on to the part of the plan where they never ever discuss this moment again, and Derek stiffens behind her - his fingers splayed out next to hers flex, the knuckles going white in her limited field of vision.

Which is when she backs up into an unmistakable bulge underneath Derek's pants.

 _Fuck_.

Casey’s brain goes blank, the wires shorting out, because…. because. Derek. And… _Derek_.

Oh FUCK.

They’re both frozen, limbs locked together, and she can feel - _it_ , she’s going to go with the IT, like a creature rising from the black lagoon to stalk women from the 1950s in old fashioned bathing suits - pressed against her backside, a hard, foreign bump wedged between their bodies. Except it’s actually _part_ of Derek’s body, a living, physical, functional part of Derek’s body that sticks out like a third elbow when he gets horny, like he’s a normal dude and not the asexual of-course-he’s-my-brother stepbrother/tormenter she prefers to think of him as, and all of this is _so very much_ what Casey does not want to be thinking about right now.

They’re not moving. Why aren’t they moving? Is it weird that they’re not moving???

Casey’s trying not to freak out.

She is trying so hard not to freak out.

She shifts her body weight, gingerly, away from the point of contact, and Derek visibly jolts and finally, _finally_ starts to move.

Derek half-falls attempting to get away from her, scrambling backward off the Twister mat. Casey stands up slowly a couple seconds later, her back still warm and comfortable from the feeling of Derek’s weight pressed down against her. It occurs to her, dimly, that she just won the game.

Last woman standing. She wins.

She won.

Derek stands up a couple feet away from her, eyes wide. He's breathing hard, jaw slack and hair messed up like he’d spent all day running his fingers through it. His erection is tenting the thick fabric of his jeans (oh god), and she tries not to stare at it ( _oh god!_ ), but come on, it’s _right freaking there_. Like, it would be weirder if she _didn't_ stare, right?

Her throat feels dry. She licks her lips, tasting tackiness and the remnants of lip gloss, and Derek's gaze falls to her mouth. His eyes go dark in this weird way she's never seen before, intense and hooded for this split-second that she hardly registers before it's gone. He takes a step backwards, away from her. His mouth opens and closes like a fish.

Derek Venturi, ladies and gentlemen, speechless for the first time in his life.

Casey would rub it in (because Derek? speechless? ~~probably~~ definitely a sign of the Apocalypse) but she only manages to mirror Derek's dorky open-shut-mouth move back at him instead. It's basically a giant comedy of errors up in here. Super awesome!

(And it's not like she doesn't know that Derek's a guy, okay. It's not like he doesn't shove a rotating kaleidoscope of girlfriends in her face, like she doesn’t fight the occasional surreal and super weird flash of attraction to him, like he doesn’t walk around sometimes with nothing but a towel around his hips and a second towel whipped up ridiculously high on his head - but she's never really put serious thought into the situation from Derek's point of view: you know, the whole Derek Is A Guy Who Wants To Bone People _thing_.)

She realizes, with a strange, awful thrill, that she now falls into the category of People Derek Would Hypothetically Bone (if Given The Chance).

Derek's eyes shift away from her, and he pulls off an almost-suave adjusting-his-pants move that makes _it_ a lot less obvious. She flushes hot and cold at how casually he does it. Like he'd done that move before.

Derek takes another step away from her. His heels hit the bottom of the staircase.

"I think… I… just…"

Which is when he makes a break for it and runs away.


	2. Intermission

**Notes for the Chapter:**

> Huge thanks to jaegermighty for beta reading this chapter, and thanks to everybody who's left kudos, comments, or bookmarks so far!

Casey wakes up the next morning determined that everything is going to be normal. Nothing happened! There's no need to freak out! So what if she'd spent half of the previous night being weirdly attracted to her annoying stepbrother, and then said stepbrother had popped a boner while the two of them were tangled up together in the middle of a highly competitive one-on-one game of Twister? It could happen to anybody, really. Totally normal. No big!

—

Her resolve lasts until she makes it to the shower.

A sticky humidity clogs the bathroom as she brushes her teeth, fogging up the mirror, because Derek forgot to turn the exhaust fan on after his shower ( _again_ ). The bathroom smells the way that Derek had smelled last night, like way-too-aggressively musky sandalwood with a faint hint of shampoo. It normally makes her want to gag, the heavy teenage boy scent too strong in the tiny room, but today it… doesn't. 

It just… doesn't.

That should have been her first warning.

She turns on the shower and pulls off her pajama bottoms and top while it warms up. The moisture in the air runs down the mirror in rivulets, her reflection obscured by steam, the air thick and humid in her lungs. She hooks her thumbs in the elastic of her underwear and kicks them off. The humidity sticks to her body, beading up in little droplets on her skin, and the whole room smells like Derek, overwhelmingly like Derek.

It occurs to her, for the first time, that some of the water collecting on her skin is from the shower that Derek took only fifteen minutes ago.

Where she is now.

Derek. Naked. Standing in the exact same place, the same steam touching both of their skin, the same molecules forming droplets of water on both of their bodies.

Naked and...

Oh god. Oh god oh god oh _god_.

She showers as fast as humanly possible, splashing soap and water haphazardly and almost pulling the curtain down when she ends up with shampoo in her eyes. She doesn't even try to dry herself off, just shoves a towel under her armpits and makes a break for it, half-blind from the burn of shampoo, leaving bare, wet footprints on the carpet as she runs across the hallway to her bedroom. She slams the door shut behind her and throws herself, face-down and soaking, onto her rumpled bedspread, breathing hard. Her skin is radiating heat, pink from the hot water.

She needs help.

Serious help.

—

"Paul," she says, and leans over his desk a little more, so that he realizes how VERY SERIOUS this situation is, "you have to tell me what to do."

Paul rubs his eyes. "I don't think I understand, Casey. Derek was…?"

"He…" She can do this. "He was… staring at me." There. That works. She just won't say what _part_ of Derek's body had been staring at her. It's a metaphor! A metaphor for Derek's ~~penis~~ unwanted attention!

"Riiiight. And why is that a problem again?"

Because… “Because it's rude."

"Staring at you is rude," he repeats, and she nods in agreement. Exactly! Paul gets it, he knows what’s…

"Why?"

 _Traitor_.

"What?"

"Why is Derek staring at you rude?"

She stares at Paul, flummoxed.

"I mean, technically," he says mildly, "you're staring at me right now. Is that rude?"

"No. No! It's just… it's different when he does it. You know. Derek is _Derek_." She loads his name up with every awful, disgusting, annoying thing he's ever done to her.

Paul lifts an eyebrow, and Casey feels a sort of fear clawing at her stomach, like he can see through to every conflicted thought she's having about Derek, the skittering sense of nervousness she's fighting tooth and nail. "I don't know, actually. How exactly is it different?"

"It just _is_."

"Humor me. What's really going on here, Casey?"

Okay, make it subtle. Metaphorical. No sweat, easy as 1-2-3.

“Okay. It’s just… he - we were fighting and there was an issue with a…“ _don’t say penis, don’t say penis_ , “…banana?”

“A banana,” Paul says flatly.

“We were, um, having a food fight? And the banana thing was really…” Switch tactics. “There was _staring_ , Paul. Staring!”

“I don’t think I understand.”

“It’s just… I think we just - _Derek_ , I mean, Derek got a little too into the, uh. Food… fighting?”

“Casey,” Paul says, visibly giving up on her sad little metaphor, “putting aside whatever… _this_ … is, you know that if you’re having a problem with Derek you need to resolve it.”

“Easy for you to say.”

“That’s one of the perks of being a counselor. Look, can you talk to your mom about the issues the two of you are having?”

She almost falls out of her chair. “No!”

“Okay. Derek’s dad, then?”

The blood drains from her cheeks as she imagines the look on George’s face. “Worse.”

“Then you need to talk to Derek,” Paul says firmly, in his most reasonable, look-I’m-an-adult-and-just-came-to-a-logical-conclusion voice, the one that Casey imitates at home when she can’t get Lizzie or Marti to listen to her. She bites her lip and scowls deeply across the desk at Paul. Why is he so good at this? It’s not fair.

“Fine,” she spits. “ _Fine._ But you know I won’t enjoy it.”

“I never said you had to,” Paul says, and takes a self-satisfied little sip of his coffee.

—

Dinner that evening is an awkward mess that consists of Derek staring intensely at Lizzie until she bursts into tears, Casey stabbing her broccoli with focused and unusual violence, and Edwin glancing back and forth between Derek and Casey with an weirdly perceptive look of interest.

“What did the broccoli ever do to you, Casey?” George asks, and Casey looks down like she’s waking up in the middle of a horror movie, knife clutched incriminatingly in her fist. She forces her fingers to relax, looks up almost reflexively, and catches sight of Derek looking at her for the first time across the table.

Derek’s eyes snap away from her, back to their previous target. Lizzie’s eyes widen as she asks to be excused from the table, only stumbling a little over the words in her haste.

Derek flees the table as soon as dinner is over, and when he comes back home that night past his weeknight curfew he locks himself in his room and ignores Casey’s frantic (quiet, polite, totally non-threatening!) knocking.

—

Casey gives herself a stern pep talk in her room before coming down the next morning for breakfast. It’s all a misunderstanding. It’s biology! They’re teenagers! There’s nothing to worry about, it’s so not a thing. It doesn’t have to be a thing.

“Hey, Der-“

“Oh, hey, Casey! What a coincidence. I have - I can’t - …gotta go!” Derek slams his open notebook on the kitchen island shut and runs out of the back door, leaving a mournful and trailing explanation of “…hockey practice?” in his wake.

Casey frowns.

—

“Hey, D, can you -“

Derek slams his locker shut and grabs Sam by the collar of his jacket, dragging him away. Sam shrugs helplessly back at her as he’s pulled by a relentless force backwards into the depths of the school.

Casey’s frown deepens.

—

“THIS IS AN AMBUSH,” she screams, and throws open the door to Derek’s room.

“ _Oh my Go_ \- oh, it’s just you.” Derek, who had jumped to his feet at her entrance, flops back down on his bed, bouncing from the impact. He crosses his ankles, puts his hands behind his head, and smirks at her over-confidently, like he hadn’t just spent the last two days fleeing from her like a mad man and hiding at the merest hint of her shadow.

“That’s all you have to say?”

“It’s an accurate statement.”

“You’re been avoiding me for the past two days, Derek!”

He shrugs, and she resists the urge to scream.

“Whatever. I need the keys.”

“The what?”

“The keys. For the _car_ , stupid. I need to go pick up Emily in an hour.”

“Oh,” he says, sounding strangely subdued all of a sudden. “Right.” 

She rolls her eyes and taps her foot to make it extremely clear just how annoying she finds this whole conversation, trying to fight the nervous feeling bubbling up inside of her. She’s hyper-aware of Derek’s room in a way she’s never been before: posters for shitty, obscure bands and B-run movies papering the walls, the battered old chair he’d rescued from George in the corner, the faint, musty male-bedroom smell of laundry and sleep and something pungent, like drugstore cologne. He hops up off the bed and rummages in the top drawer of his desk before tossing the keys to her. She threads her pinky finger through the metal ring and flattens the keys against her palm, heavy and reassuring.

Derek collapses back on his bed, grabs a magazine, and pretends to read it for a whole three seconds before glancing back at her as if surprised to find her still gawking in his room. “You’re still here,” he points out obnoxiously.

Casey shifts her weight to her other foot. She thinks about what Paul said. She looks back at Derek, lying on the bed, t-shirt riding up his torso, the heavy buckle of his belt across his hips, and she can’t make the words come out.

“Derek,” she manages to croak out finally.

“What,” he says. It’s not a question.

“I…” She draws a deep breath. “We… Derek, I mean… I… just wanted to say that. Um.”

She swallows hard, and doesn’t say anything else.

He stares at her, shoulders tensed like he’s about to bolt. And Casey is suddenly, painfully aware that Derek is lying on his _bed_. Has Derek ever had a girl up in his room before? She’s never made out with a boy on a bed before, just couches and pressed up against the brick wall at school and a couple times in the backseat of Max’s car, but never a _bed_. The idea seems overwhelmingly _adult_ somehow, in a way that makes her stomach twist up with a awful sort of nervousness. He probably has. He’s probably had his hands on some girl’s hips and his tongue inside her mouth, and Derek had probably rolled them so that he could press himself against her thigh, press…

“I-just-wanted-to-remind-you-that-I-have-the-Prince-for-the-whole-month,” she blurts out. “Because I won. I’m the winner.”

Derek doesn’t say anything.

“So ha,” she concludes weakly. She backs up a couple steps toward the door, still facing Derek. “…And I’m going to leave. Now. For the party. With Emily.”

“Okay,” he manages to say.

“Right,” she agrees. Her hand, grasping for the door knob behind her, finally connects with the cool, curved metal, and makes her escape.

—

After that, things go back to mostly normal for a while.

It’s like Derek can sense that she totally chickened out on having The Talk with him, and he throws himself back into life with the gusto of a man pardoned from death row. Except - and it takes her a while to even figure out that this is something different, that this is now something _weird_ about their relationship now - he stops touching her.

Just. Stops touching her.

He chucks items at her head now instead of handing them to her - the remote, her book bag, a water bottle after one of his hockey games - and laughs like a hyena if she bobbles the catch. He shifts away from her if they end up sitting next to each other in the backseat of the car. He stops bumping up against her whenever they walk down the hallway, the way he used to throw his arms around her shoulder to steer her around, whispering stupid, annoying little taunts in her ear. She’d never realized how much they touched casually until it becomes a vacuum in her life.

That’s a weird thought all by itself.

—

“It’s great to see you getting along with Derek,” Nora says, and plops the last, gloopy spoonful of mashed potatoes into the serving dish.

It startles Casey enough to look up from her homework.

“What?”

“You and Derek,” Nora repeats, looking with a concerned frown down at the precarious tower of potatoes in the bowl.

“Me and Derek _what_?” she repeats warily.

“You seem to be getting along right now. I mean, I can’t remember the last time either of you put the other in a headlock.”

“Derek put me into a headlock yesterday,” Edwin points out.

“See?” Nora beams at Casey, happy to prove her point. “I knew the two of you were getting along better.”

“Casey’s getting along better with who?” Derek asks, swinging the back door open and throwing his bag of hockey gear on the ground.

Edwin’s eyes go wide and Casey draws her hand across her neck a couple times in a _cut it out_ gesture, but Nora just grins the optimistically oblivious grin of a mother who thinks all of her children get along and turns toward the door.

“I said, it’s nice to see you and Casey getting along better lately, Derek.” 

_Great._

Derek gapes at Nora, then doubles over laughing, clutching at his side theatrically. Ugh, it’s not THAT funny to think the two of them could get along for a couple weeks or whatever.

“Good one, Nora,” Derek finally manages to gasp, and throws his hockey pads at Casey’s head, hitting her homework and sending it flying off the kitchen island, just to prove his point.

—

“Hey, Case,” Derek says, and drops into existence next to her on the couch, “I know you have the car for the month, but I need the Prince this Saturday.” His tone is that maddening hybrid of unbreakable confidence and lazy arrogance that reeks of Most Popular Guy In the School-itis, the way he sounds when he assumes nobody is ever going to say no to him, ever.

Casey draws her blanket closer to her body, staring fixedly ahead at the screen. “Forget it.”

“I knew you’d say that. I’ll _trade_ you for it.”

“I won that car fair and square, Derek.”

“Trust me, Casey, asking for this pains me more than it pains you, but-”

“I doubt that.”

“- I happen to know that Emily’s coming over on Saturday, so you won’t be using the car anyway.”

Casey narrows her eyes. “Who told you that?”

“Lizzie.”

“That _traitor_ ,” she breathes.

“So -”

“I said forget about it, D.”

“But -“

“Why do you need the Prince so badly anyway?”

“I,” Derek announces, like this entire conversation is building up to what he’s about to say next, “have a _date_.” He looks so pleased with himself that Casey wants to actually throw up in her mouth a little. Like they hadn’t just established that Derek’s attracted to anything with boobs and a pulse, even when it was Extremely and Very Morally/Ethically Wrong to be attracted to said person, and it made everybody involved feel tense and wrong and guilty about things they they had no reason at _all_ to feel guilty for!

Boys are the WORST. He probably only told her about his terrible date to get a reaction out of her. For all she knows, his date doesn’t even exist. Derek’s taking Invisible McDoesNotExist to the movies, just so he can rub it in her face. She feels anger and annoyance rise in her like a heat.

“Pick her up on your bike, then.”

“On Louie?” Derek asks, looking honestly concerned, and she always forgets that Derek had named his bicycle as a kid, because he’d really loved the stupid thing.

“ _Walk_ ,” she suggests, gritting her teeth together. “Hold hands and skip down the sidewalk together. I don’t care.”

“I have a _hot_ date, Casey,” Derek clarifies. “This is a Prince-level code red situation.”

“I don’t _care_.”

“I knew a washed-up social reject like you wouldn’t understand.”

“Are you deaf as well as stupid? I said no. N. O. No.”

He crosses his arms over his chest. “I wouldn’t do this to you, you know.”

She actually laughs. “Uh, this is exactly what you did to me when I wanted to go to the party with Emily a couple weeks ago.”

He ignores that. “I said I’d trade you for this weekend,” he points out, like she’s the one being unreasonable.

“Okay, I’ll bite. Trade what?”

“I’ll do your chores for the weekend.”

“Boring. Try again.”

Derek pauses, a weird look of uncertainty showing on his face. Terror and adrenaline flood Casey like a shock. If he mentions _it_ , if he says anything about -

“I’ll play you for it,” he says instead. He says it normally enough, but she knows Derek well enough to see a flicker of deep uncertainty.

It occurs to her for the first time that Derek - the man with the plan, the guy who always knows what’s going on - is just as much in the dark on this one as she is.

Maybe she can use this.

Okay. Let’s pretend she’s actually going to consider his terrible suggestion. It obviously can’t be anything physical. Nothing with touching. Nothing where…

"Poker," he says abruptly. “We could play poker.”

Derek had been the one to teach her how to play poker, in a rare truce they'd called the first year. He'd been laid up for a couple days with a bum ankle after a game, practically vibrating out of his skin with energy, and Nora and George had shoved her upstairs with a deck of cards and the firm command to _just keep him busy for a while, okay_? 

She’d actually _liked_ playing poker with him, before. It had been... nice. Her mom and George had let them play until past their normal bedtime, and Derek had been uncharacteristically easygoing with his ankle elevated and doped up on a hefty dose of pain meds, the two of them sitting his bedspread. He’d taught her trick taking and card counting and how to read tells, and she really didn’t think there was anything he’d kept up his sleeve for later. He’s better than her at bluffing, true, but at least it wouldn’t be a horribly uneven playing field. It’s as good a shot as she’s going to get with somebody like Derek.

“What do I get if I win?” she hedges.

Derek hesitates again, and Case’s confidence jumps up another notch. “Another month of the Prince? And if I win, I get the car for this weekend and then we go back to splitting it.”

That’s a crazy good deal. CRAZY good. She pretends to consider it for half a second, then sticks out her hand before Derek can come to his senses and take it back. Derek shakes her hand, and Casey only realizes after the fact that this might be the first time that they’ve touched since everything ended up all strange and wrong between them.

"Tonight?”

He nods. “Okay.”

—

Casey dresses for battle. She wants to win this game; she can’t let Derek win, just so he can take some terrible girl out on a shitty date in HER car.

She thinks about the way he doesn’t touch her anymore, the way he acted so strange around her after… _after_. She pulls on a tank top, puts both hands on her hips, and considers herself in the mirror.

Then she sneaks over into Derek's room and digs through his dirty laundry. Ugh, like she needed any more proof that boys are terrible: everything has dirt and stains rubbed into it, and all the gear remotely related to hockey has the musty sourness of old sweat. Casey shudders, puts her nose up in the air, and pinches it shut. Somebody should give her a freaking _medal_ for this. She unearths a single white athletic sock from the bottom of the heap; it's stiff and a little crusted, wadded up the middle, and Casey stares at it way too long before it occurs to her what she's dealing with.

“ _Eeew_!” She throws it back in the pile of laundry and tries to wipe her hands clean on her jeans. Double eew!

(She very, very carefully does not think about Derek staring at her in their darkened living room, breathing hard and eyes dark and strange for that split-second.)

She spies the sleeve of Derek's game jersey, rolled up into a ball underneath a pair of laced hockey pants, and makes a break for it. She washes her hands with the strongest stuff she can find while treating Derek's jersey to the same treatment in the washing machine.

An hour later she declares both her tainted hands and the jersey to be at a baseline, minimally acceptable level of disgusting. She pulls on Derek's jersey in her room and spends a while messing with the neckline, slumping her shoulders to see how much she can get the collar to slip down and show the white straps of the tank top underneath.

It's… not really sexy. She's seen the girls wearing their boyfriend's practice jerseys around school. There's got to be a better way to do this.

Casey chews at her lip, and takes the tank top off. Derek's jersey swamps her without the extra layer of clothing underneath, the fabric billowing out in thick folds around her torso. She doesn't really think about their respective sizes much (she feels that both of them take up about the same amount of space in a room), so the fact that two of her could fit inside one of Derek's jerseys is seriously messing with her world view. It's probably all the padding he wears underneath.

Without the tank top her bra strap is a line of pale pink against her skin, peeking out of the collar of the jersey on left shoulder. The strap, however, is thin and elastic and kind of cheap looking. Thumbs down.

She slips the bra off and pulls the jersey back on over her bare skin. And wow, that just upped the weird factor to, like, _eleven_. Casey shivers involuntarily (because the jersey is disgusting and it is touching her _everywhere_ and why didn't she run it through the heavy cycle in the washer three more times?) and her nipples tighten up (it's a _natural reaction_ , she chants to herself). The mesh of the jersey feels strange and open next to her skin, like there's a constant breeze coming in through the porous fabric. The stitching around the numbers and logo keep rubbing annoyingly against her now-hard nipples.

Casey presses the palm of her hands against her chest, flattening her breasts, in an attempt to to stop the friction.

But - she looks _good_. It's the best option she's tried. The collar is slumping attractively down her naked shoulder without the friction of fabric underneath. She experimentally pulls her hair into a low single side-ponytail, away from the bared shoulder. It makes the slope of her neck look long and elegant, like a ballerina. It's pretty. Not that _pretty_ is something Derek would appreciate (really, it's totally wasted on him), but she figures that just wearing the jersey is going to give her the edge she needs to win this thing anyway.

(That, plus the extra ace she has tucked away in her back pocket. What? She knows Derek will be doing the same thing. That part just makes them even.)

She drops her hands down by her side to assess the nipple situation in the mirror. The jersey is so huge that it stands away from her body, and the logo sewn to the front is a thick, inflexible fabric, like a patch or a badge. It seems like a good shield. She should be fine.

She yanks the jersey off, shoves it under her bed, and changes back into a regular old t-shirt for dinner.

—

Derek throws a buttered dinner roll at her face at dinner, and informs the table that the new skirt she bought last weekend at the mall is the ugliest thing he’s ever seen in his entire life. She nails him in the shins underneath the table in retaliation.

Casey is _so_ looking forward to wiping that smug grin off Derek’s face later that night.


	3. Poker

**Notes for the Chapter:**

> Thank you to htbthomas for pinch-beta reading this chapter for me. <3 And thank you again to everybody who has cheered this story on so far!

She changes in her room and makes it halfway down the stairs that night wearing Derek's jersey before she realizes: nope. Nope nope _nope_!

This was a _terrible_ idea. What was she thinking? She feels jumpy and half-naked, nipples rubbing annoyingly against the scratchy lettering, and wearing Derek’s _jersey_ , of all things. His jersey! This is so dumb. This is a girlfriend move. The realization drops the trapdoor out from under her stomach. This is the absolute stupidest -

Derek looks up from where he’s sitting at the dining room table, and his jaw drops.

Oh.

Oh crap.

She can’t run away now without being outed as a total coward, so she throws back her shoulders, lifts her chin, and descends down the staircase like this was definitely the plan all along. Breathe in, breathe out. Glide! She is Scarlett O’Hara in a gown sewn out of hockey jerseys, she is Anne Hathaway post-Princess Diaries makeover and any eyebrow waxing montage, she is any of the girls in the old black and white movies her mom loves, during the scene where the boy notices her, actually _notices_ her for the first time. Which… wait, what? No. Not the last one. Definitely not that last one.

_Get it together, Casey._

Derek snaps his mouth shut and his eyes drift away from her. The muscles of his jaw flex before he speaks, the line of his throat working, Adam’s apple sliding up and down.

“Are you trying to ruin my jersey or something, Grosszilla?”

It’s such an aggressively normal, _Derek_ thing to say she could almost hug him. Almost.

“What, by washing it?” She pulls the collar of the jersey up close to her face and sniffs it. “Yeah. Totally ruined. How will you ever survive?”

Derek’s mouth tightens, but he doesn’t say anything.

“What?”

“You…”

“…What?”

His tongue darts out between the white of his teeth and he mutters, “I am never going to win another game wearing that jersey.”

“That’s the plan,” she says brightly, feeling suddenly more confident. She takes a seat across from him at the dining room table, tucking an ankle up underneath her. He tosses her the deck of cards, looking wary and silently angry all at once.

“Your deal, Princess,” he says, because she would always take first deal when they’d played before. She feels a strange little stab of guilt, like they’re tainting one of their few decent memories together with… whatever _this_ is, whatever she’s doing playing poker with Derek while wearing his hockey jersey, sans one very important bra.

Her thumb slips on the worn edge of the cards as she halves the deck, sending half the stack flying, a klutzy slip that Derek would normally be all over like the most annoying butter ever on perfectly okay toast, but he just leans over to pick up a few cards and hands them back to her without a word.

She finishes her impromptu round of 26 card pickup, shuffles a few more times, and slides the deck at him to cut.

—

Derek loses the first couple hands in a spectacularly mediocre fashion. He’s not playing well: he keeps staring at his cards like he plans to develop x-ray vision and burn a hole through whatever he’s been dealt. He’s blatantly ignoring her, tells and all. It’s kind of like shooting fish in a barrel, only way easier.

“‘Cause I’m the wiiiiiin-ner,” she sings, aiming somewhere in the vicinity of the chorus from _Thriller_ , and rakes in a pile of poker chips. “Winner, winner, wiiiiiinner.”

Derek rubs his forehead. His gaze keeps slipping sideways whenever he looks up, like she’s the sun and he’s waiting for an eclipse. Honestly, she’s feeling kind of smug about it. “Stuff a sock in it, will ya, Case.”

“Gosh, Derek, is somebody a sore loser?” She sings into her fist like it’s a microphone. “Loooo-oooh-ooohser.”

“I am _not_ a sore loser,” he snaps, scowling down at his cards, disproving his entire hypothesis in one fell swoop. “You’re the one who’s a bad winner.” He throws a single chip on the table between them.

As if! “ _I’m_ a bad winner?”

“You’re a bad winner,” he repeats.

“Have you ever even looked at yourself in the mirror? Pot, meet kettle.”

“I said, shut up, Case.”

“You’re just angry ‘cause you’re going to be rocking a 10 speed for your awful date this weekend,” she says, triumphantly.

Derek doesn’t respond to that, just gestures sharply at the table, looking kind of honestly annoyed now. Casey glances at her hand, a pair of low-numbered suit cards in mismatched colors, and prudently folds.

The universe rewards her smart play by gifting her a set of paired red aces in her hand on the next deal. Casey slams the faces back down on the table and tries to make her face look calm. She feels like she should be better at this part, better at bluffing, and tries to console herself that she only sucks at it because she’s such an honest, open-book kind of person. Derek’s good at poker because he’s a cheat and a liar and probably nags the cards into doing what he wants with his annoying face.

Derek rolls a chip on its edge before throwing it in to call.

Casey baits Derek upward carefully. The flop yields nothing she can use, but _c’mon_. She has a freaking _pair of aces_ in her hand. But then Derek turns over the fourth card on the table, and she sees the possibility of the straight for the first time and retroactively starts to feel nervous about how steadily Derek is playing his own hand. He could be doing the same thing to her, trying to keep her in this hand, trying not to spook her. Trying to lure her in. Like a siren. A poker-playing siren who is also a dude.

Derek raises, a larger pile of chips this time, almost doubling the amount already in the pot. It’s a put-up-or-shut-up move.

Casey hesitates.

…He could be bluffing.

“Your move,” Derek says, like she doesn’t already know that.

“I’m thinking,” she says, too fast, and winces when Derek narrows his eyes at her. Stupid!

She tucks a leg up underneath her, leaning forward onto her knee at the edge of her chair. Her side-ponytail swings toward her cards, and the jersey slips down her bare shoulder. She frowns at her cards (look like she’s unsure of her cards, she’s a good actress, she can totally do this!) but when she looks up again Derek’s staring at her absently, not even paying attention to the awesome bluffing game she’s putting up for his benefit.

His features are strange and slack, his gaze locked somewhere below and to the left of her chin, in the vicinity of the slipped jersey collar. He looks zoned out, like he doesn’t even realize what he’s doing.

He’s… he is definitely checking her out.

Oh god! Is she flashing him? Did she do the test where she pulled the jersey down to check out the maximum cleavage she’d had to deal with? She panics about him staring at her hardcore for half a second before remembering that this, right here - this was her _plan_. This is what she wanted to happen! Distract, disarm, _win_.

She can do this.

She can _do_ this.

Casey takes a deep breath, ignoring the bad feeling slipping around in her gut. She flexes her foot underneath her, leans forward onto her heel, and plants her elbows on the dining room table. She shrugs her shoulders together so the shoulder slips down another inch, exposing more of her chest. Her boobs are caught between her arms, using her triceps as a push-up bra. The motion shifts the scratchy fabric of the lettering against the front of her breasts again; her nipples are feeling almost sore by this point from the constant agitation, tight and itchy-red, and she’s super glad they’re at least shielded like this, hidden from view underneath the same thick fabric.

Casey looks back down at her hand, frowns deeply and theatrically (it’s called ACTING for a reason), and sneaks a glance back up at Derek to judge his reaction. She’s still not sure if she should call or fold. She’s hoping to catch an unguarded expression on his face, anything to give her some sort of guidance.

Instead, Derek is staring straight at her, eyes sharp and locked on her own, for the first time that evening. She can almost see the little clockwork gears turning in his brain, churning out terrible, self-centered teenage boy answers to all of the world’s questions.

Casey realizes, with the sudden, blinding clarity of foresight, that her plan to get the upper hand with Derek has a fatal flaw.

And that’s when Derek leans forward, elbows on the table, just like her, and asks, in a low voice, “Why are you wearing my jersey?”

Why _is_ she wearing his jersey? Because…

“Because I wanted to win.” She makes herself sound disinterested when she says it. Sharp. Like a James Bond lady-villain or something.

Her honesty knocks him back for a minute, she can tell that much. He doesn’t say anything as she counts out a short stack of chips and tosses them into the center of the table. Derek stares at her across the table, then flips up the final card. It’s the three of spades, which fits right into the straight and leaves her with her lonely, standalone pair of pocket aces.

He raises one last time. She hesitates, then calls.

He nods at her. “Moment of truth.”

“Read ‘em and weep,” she says, laying out her hand with more confidence than she feels.

Derek, though, as it turns out, doesn’t have the straight. He has a seven in his hand, matching the highest card on the table, but that’s it. He’s bust. She just won again! Ha! Take that, world!

“ _Wiiiiiiinner_ ,” she crows, and sweeps her earnings with the flat of her hand.

—

He’s tapping his dwindling stack of chips thoughtfully a couple hands later and staring at his cards when he asks, “How much would you give me for my sock?” And then he plops one of his giant, disgusting feet up on top of the kitchen table and wiggles his athletic sock-clad toes in her direction.

She shoves futilely at his ankle. “ _Derek_! We eat _food_ off this table.”

“And here I thought we were one of those civilized families that ate off a little thing I like to call a plate.”

“You know what I mean.”

“Humor me. How much for the sock?”

“I am not playing _strip poker_ with you, Derek,” she hisses, the words out of her mouth before she really considers what she’s saying, and to whom. She stumbles onward into the vacuum of silence created by her words, driven by a horrifying sense of terror, forcing disdain for the entirety of Derek’s life choices into her voice. “I mean, what would I do with one of your socks? Gross.”

There. Nailed it.

Derek holds his hands up, palms out, the picture of innocence. “Hey, what you get up to in the privacy of your own room is none of my business.”

That’s the type of disgusting, vaguely suggestive thing he always says to her. Right. Nothing more than Derek being stupid Derek Venturi! Just another day in the life.

Casey jabs at the ball of his foot, hard, with a single finger. His toes spasm inward a little from the contact. “Fine. One chip.”

“A single chip?” Derek cries, affront written all over his face. “These are game-time winning hockey socks, Casey. These socks and I have been through a lot together. Losing this sock would be like losing a brother to me.”

“You’re saying that you rank a single smelly, off-white sock and _Edwin_ on the same level.”

“Edwin knows what a compliment that it is.”

She rolls her eyes as obviously as possible. “Two. Final offer.”

“Done,” he agrees, so quickly that Casey is pretty sure all of a sudden that she’s been had. He grabs the cuff of his white, calf-high athletic sock and strips it off. He tosses it on the dinner table turned inside-out, the indentions where the ribbing were still showing red on his leg, the dark hair of his leg matted down flat against the skin.

Casey wrinkles her nose and tries not to think about it.

—

“But I _love_ this necklace,” Derek says, leaning toward her with his thumb hooked under the black cord, holding it away from his chest on display. “I can’t believe you’re only offering me five chips for it. Why don’t you just kill me now, Casey. It would be more dignified.”

Casey leans back in her chair, fiddling cheerfully with the chain of her own necklace. She knows the price she sets for Derek’s necklace is going to impact the price of her own, and also the price she might be able to get for her earrings.

She balls her hands up into the long sleeves of Derek’s jersey, and leans her chin against fabric-covered fists to think.

Derek’s list of assets right now include: 12 poker chips, two socks (one his, one hers), the brown hoodie he’s wearing, and the metallic circle necklace he’s currently pushing on her. Maybe his t-shirt. Her own assets are: 38 chips, two socks (one she’s still wearing, and Derek’s disgusting sock, on the floor next to her), her silver charm necklace, and a pair of hoop earrings. The jersey is obviously a no-go, as are both of their pants (his cargos, her jeans).

Because, Casey tells herself firmly, they are _not_ playing strip poker. No sir, not even a little bit! They’re just buying and selling personal possessions as part of a friendly game of sibling-style poker; this is basically the platonic version of cards crossed with a yard sale, or something.

She should go up. It’ll increase her own bargaining power if she ever needs to put the earrings down.

“Six,” she agrees, and Derek only hesitates for a moment before nodding and ducking his head to take the necklace off, throwing it on the table.

Casey glances down at her own cards again and pushes in six chips to match.

—

“Raise,” Derek says, and throws in the silver hoop earring she’d lost to him a couple of hands before. 

Casey’s hand drifts up to touch the single earring she’s still wearing, considering her options. She has two hearts in hand, one away from the flush. It’s not bad odds.

“You look like a pirate with that earring,” Derek says, watching her. “All you need now is a pointy hat and the broomstick.”

“That’s a witch, Derek, not a pirate,” she corrects absently. If she pulls the flush she’s pretty sure there’s nothing on the table that can beat her, even if Derek has a three-of-a-kind hidden away in his hand. She should go for it.

“You said it, Case, not me.”

“You’re hilarious.”

“You’re stalling.”

Casey reaches up to undo the clasp on her remaining earring, working the locking mechanism by touch. She tosses it on the table to match the one that Derek raised with.

The next card comes up a heart. Casey rakes both of her earrings back in along with a tidy pile of chips, beaming.

—

“So who’s the date with, anyway?”

Derek fumbles the chip he was flipping, front to back, then clears his throat.

She cups a hand to her ear. “What’s that? I couldn’t hear you.”

Derek mutters something under his breath, and Casey grins.

—

Derek keeps losing, slow and steady, which culminates in Casey winning both his second sock and, in a moment of sheer and unmatched-in-her-life-so-far triumph, his faded brown hoodie. She pulls the hoodie on over the jersey, grateful for a second layer to warm up the chill from the air constantly moving through the mesh fabric, and hooks her palms in the worn cuffs. It makes her feel like her covered up, a little less aware of her nipples (which are _killing_ her) and her neckline (which slips down all the time, seriously, why did she think the jersey was a good idea again?).

And then she deals herself another potentially winning hand - a four and a six of spades, with the matching five already on the table in the flop.

Derek raises, and she counters big, knowing she’s about to put him all in with his teensy pile of chips. Except she’s sort of not ready to stop playing. She’s actually having fun. She’s buzzing with pulling one over on Derek, fair and square. She hasn’t even needed to pull out the emergency ace she has stashed away in her back pocket. Seriously, this was _such_ a good idea.

“I’ll give you fifteen for the shirt,” she offers. It’s one of his old D-Rock tees, stretched out and worn at the collar. Unlike the hoodie, which Casey is pretty sure she’s going to be forced to return at some point after tonight, she might be able to steal the t-shirt for good if she wins it now; it’ll make a great pajama top, beaten-in and comfy. She’s anticipating it already - it’ll be like rubbing her victory in his face whenever she wears it. She likes the idea of ~~his~~ her t-shirt being a lifelong reminder of Derek’s many defeats and failures as a human being. She’s pretty sure it’ll be poetic justice.

“My shirt,” Derek repeats, sort of slowly, like his tongue is suddenly too thick in his mouth.

It’s his tone that causes her to reassess her offer, and - oh. _Oh_.

It isn’t weird for Derek to take off his shirt in front of her, though! She’s seen him shirtless way more than she’s ever wanted to - to do chores in the backyard in the middle of summer, to play skins and shirts field hockey with the guys, harassing her in the hallway outside the bathroom after he takes a shower, trying to wheedle her into doing whatever homework he has due that day. She steals his shirts sometimes to wear when Nora gets behind on the laundry - it’s not a _thing_. It’s totally brother/sister appropriate. _Totally_.

But her protests die on her tongue, and she swallows her denial back at the odd look on his face. Her heart starts rattling around in her chest like a tea kettle at boil.

He doesn’t say anything, doesn’t grouse about her lowball offer (he should really be bartering her up to twenty chips, at _least_ ). Instead he grabs the collar of his t-shirt behind the back of his neck, hesitates for a moment, and then decisively yanks his shirt off over his head, the one-handed pull that all boys seem to do. She can see the lean muscles of his torso slide and cord as he moves, skin shifting over faintly visible ribs.

She feels suddenly hot, like when she had that bad cold last year that broke out into fever, the way her skin crawled with heat and she couldn’t seem to stop shivering.

And there are the same old dumb splotches across the tops of his shoulders that he’s always had - discoloration from the sun, or the remnants of acne, or maybe a faint sprinkle of freckles across his collarbone - she’s never been able to decide. There’s a farmer’s tan line of white across his bicep where his t-shirt sleeves hit. His chest is narrower and a bit bonier than she knows he wants it to be, the whole of him lean from a recent growth spurt and doing suicides at hockey practice, but he’s got a little bit of chest hair now that he didn’t have when she first met him, thin and and wiry, sprinkled across his breastbone. She can see the rounded pull of muscle around his shoulder joints.

He wads his shirt up into a ball, but hesitates before throwing it on the table.

“Fifteen, right?”

She nods dumbly, and he tosses it onto the pile of chips and his own left sock. She looks down at her own hand again in a haze.

She throws in a stack of chips to match, swallows, and nods at Derek to deal the last card. 

It’s a diamond.

He huffs out a sharp breath like he hadn’t even been aware of holding it, and pulls in his winnings, including the t-shirt. Casey shifts uncomfortably, digging her thumbs deep into the stretchy cuffs of Derek’s hoodie, while her stepbrother keeps sitting in front of her shirtless, shuffling the deck like what he’s doing is the most fascinating thing in the room.

He should really put the shirt back on.

Seriously, why isn’t he putting his shirt on? Derek won his dumb shirt back. The least he could do is put it back on! What if somebody walked in on them? They would be in so much trouble, it’s not even funny.

Although… Casey isn’t really exactly sure _why_ they’d be in trouble. Sure, it’s kind of weird that Derek is sitting around shirtless for no obvious reason, but it’s not like it’s exactly unheard of or anything. But she’s sure in her gut that George and Nora and everybody would be able to look at the two of them and know that whatever she and Derek are doing here is wrong. They’d _know_.

“Cut?” Derek asks, interrupting her spiral of shame, and she looks down at the deck of cards pushed in front of her. She splits the pile.

Derek sweeps the cards back in and deals.

—

Casey starts to lose.

She blames Derek’s nipples. They’re just so THERE, in her field of vision, pebbling as much as she supposes a guy’s nipples ever would in a slightly chilly room. And when she tries to move her eyes she ends up staring at his small patch of chest hair instead. At the mole over his fifth rib. At the pale white of his stomach, and the thin line of short hair trailing down from his bellybutton. At the way his shoulders are hunched forward a little, visible tension playing across his muscles.

And Derek’s nakedness just makes her even more aware of her _own_ nipples, which feel crazy obvious now, a tight, throbbing red underneath the rough fabric of Derek’s jersey. She feels like a car with both headlights on high beam, in the worst possible way that could have happened.

She loses her little pile of jewelry first. Derek’s necklace and her silver earrings go next. They trade chips back and forth on a couple even hands before, in a burst of terrible decision making, she loses all four socks in one go.

They’re not talking much now.

—

“Pay up,” Derek says, and holds out his greedy, greedy hand.

She pulls her arm slowly out of the sleeve of the hoodie, rubbing a hand up her arm to fight the chill raising goosebumps on her skin. How is their dining room so _cold_ right now? Don’t their parents pay the heating bill?

She hands the hoodie over reluctantly. She feels crazy exposed without it, which is kind of strange because she hadn’t actually been wearing it for that long. Derek gleefully adds the hoodie to his pile of winnings by his feet and deals the next hand. 

Two black aces come up in the flop. Casey takes a deep breath and sneaks a peek at her own hand.

She has the ace of hearts and the five of clubs.

Yes! It’s like she can feel the planets aligning, a chorus starting up all around her, the ace of diamonds burning a hole in her back pocket. This is it. THIS IS IT. She has to make her move. She has nothing left to barter with, and she’s looking at a four of a kind. There’s no way he can beat that.

She tosses the last of her chips in the pile, then hesitates.

…What if, somehow, he _can_ beat four aces?

Derek must notice her hesitation, because he leans forward suddenly.

“I’ll let you throw in the jersey if you want,” Derek says, “which I know you stole from my room, _Casey_.”

Casey feels a weird, tight flutter of panic, because, uh, _what_.

“Keep dreaming, loser,” she says, putting a hard snap in her voice with some effort.

He sits back again, shrugging, so painfully fake-casual she’s pretty sure she could read it from a mile away. “An eye for an eye and a shirt for a shirt.”

“I think you mean a tooth for a tooth.”

Derek doesn’t say anything to that, just snaps his teeth together at her, audibly clicking the enamel, and she’s actually ashamed at how hot she finds the gesture. He leans forward again, like trying to talk your stepsister into ditching her shirt and stripping down to nothing but her bra is something that is normal or in any way okay.

Which, for the record, it is totally NOT.

“C’mon, Case,” Derek continues, and there’s something wrong with his voice now that she can’t quite put her finger on, like maybe he’s talking too fast. “It’s not like it’s anything I haven’t seen before. I’ve seen you in your bathing suit before, I mean, get over yourself.”

She should do it. She should! That’d shut him up so fast, with his goading mouth and the way he thinks he’s got the upper hand right now. She can almost imagine the slack-jawed look of shock on his face if she ripped her shirt off over her head. Imagining the way he’d look makes her feel powerful. It make her feel in-control.

She crosses her arms over her chest instead, trying to ignore the crazy fast thumping of her heart. “That’s not the same thing and you know it.”

“You got my shirt off. Fair’s fair.”

“Just because societal expectations vary unjustly between the sexes doesn’t mean I’m going to take my shirt off, Derek.”

“ _My_ shirt,” Derek says.

Doesn’t he realize she’s not wearing a bra?

“No way,” she manages.

“My jersey.”

“Nope.”

Derek’s voice drops then, goes serious and earnest in a way she can hardly understand, and he says, “You know, it’s not like we’re actually related.”

Which isn’t what she was expecting him to say at _all_.

She feels dizzy. Derek’s sitting across the dining table from her, a shirtless boy on a wooden chair, and it should be ridiculous but it just… isn’t.

She reaches up to rub her shoulder, where a bra strap would be if she was wearing one, and Derek’s eyes follow her fingers. There’s this strange beat of a moment between them, and then his eyes widen, and she thinks, _oh_. Oh shit! She’s pretty sure Derek just figured out the whole no-bra thing. _Shit_.

She opens her mouth, tries to say something. Closes it again.

We’re not actually related.

That’s what he thinks of her.

“Pants,” she says, biting the word off. “How much will you give me for my pants.”

She stands up.

His eyes follow her, not speaking. She’s never had anybody look at her like Derek is looking at her right now, dark and dumb-struck, kind of like he had for that split-second after the Twister game, and oh god, just _thinking_ that makes her remember how wrong this is! Derek’s her stepbrother. Her _brother_. It’s a fact she’s reminded herself of every day since her mom sat her down to tell her that George had proposed, which means that Casey is about jump off a cliff where the only reasonable way to describe her actions will have to technically involve the word _incest_. This is so messed up, this is _beyond_ messed up, this is majorly, grade A, what-the-fuck-are-you-thinking-Casey MESSED UP.

But she is _not_ going to let Derek win this one. She is NOT going to lose.

_We’re not actually related._

She reaches up underneath the long hem of the jersey for the button of her pants, her hands only shaking a little bit. She undoes the button, then grasps the tab of her zipper, yanking it down. She can hardly hear the noise the zipper makes over the pounding in her ears. She slides her fingers back along the waistline of her jeans and grabs the ace of diamonds she has hidden in the back pocket between her two fingers like a lifeline.

“How much?” she asks again. Her voice sounds strange to herself. Distant.

Derek shifts in his seat and doesn’t answer her for a long couple seconds. “Um. Twenty… five.”

“Thirty,” she counters, and rubs her thumb, hidden, over the elastic band of her underwear.

Which - wait. Her underwear. What color is her underwear? Purple? White?? She racks her memory. Derek’s jersey is big on her, like a dress, reaching almost halfway down her thigh (so no problem there!), but it’s also sheer. And jersey mesh plus brightly colored underwear is so not a situation that Casey wants to deal with.

She risks a glance downward, but she can’t figure out how to find the color of her underwear without giving up the whole game. Just how awkward would it be if she blurted out that she had to pee right now? She could run away and lock herself in the bathroom to check and, once she lost her nerve, probably never ever come back out again.

It sounds like a pretty great plan, honestly.

“Okay,” Derek agrees finally, and his voice goes all strange again when he says it, sort of rough and higher pitched at the same time. “Thirty.”

“Thirty,” she repeats, just to buy herself time. How good are the bathroom locks? Maybe she could convince Lizzie to sneak her food through the small vent above the shower.

Derek swallows. “Okay.”

Uh, right.

Here goes nothing.

She yanks her jeans down from underneath the hockey jersey before she can chicken out, pushing the waist down over one hip, then the other. She steps out of the legs, trying not to dance around when her jeans end up caught around her ankles. She drops the ace behind her on the seat of her chair for safekeeping. She tries to do it as inconspicuously as possible behind her back, smooth and incognito-like.

She’s horribly, writhingly conscious of her bare legs as she sits back down. She can feel the waxed paper smoothness of the playing card, her ace in the hole, sticking to her left thigh underneath her.

She shifts on the chair. Cold seeps through the thin mesh of the jersey underneath her, bare skin in a place where she eats dinner every evening with her family. Where she’d sat a couple hours earlier while her mom and George had flirted over a serving bowl of peas for, like, five minutes straight until all of them had plugged their ears and glared at George and Nora until they’d finally stopped, and oh god she should NOT be thinking about her parents right now.

She looks down at her hand again to reassure herself. The two black aces are still sitting on the table. That’s good. The ace of hearts is tucked away safely in her hand. No mysterious disappearances there. That seems promising too.

There’s no way that Derek can beat four aces with anything he could have in his hand. No way at all. Although… the chance of him having the actual ace of diamonds himself is a small but definite risk. 

She has to take that chance, though. She can’t lose, she just _can’t_.

She lets her gaze slip lower for a second, down to her lap.

(Pink. Her underwear is pink.)

Derek shakes himself and tosses the hoodie back on the table, along with both of her earrings and a couple chips to round things off. He’s moving kind of weird, like he’s on auto-pilot or something. Casey feels numb, disconnected, like the crazy tension humming through her body is happening to somebody else. There’s no way she’s doing what she’s doing right now. She is not the kind of person who plays ~~strip poker~~ dumb games with her stepbrother that end up, somehow, in partial-but-still-totally-respectable-bathing-suit-areas-mostly-covered nudity! This isn’t her at _all_.

Okay, game plan: she’s going to win her jeans back, win Derek’s hoodie back, and they never talk about this again.

Derek flips over the fourth card. It’s the three of spades.

She’s still good.

Derek shifts again, and eyeing her small pile of remaining chips. He counts out a similar stack from his own stash and throws them into the center of the table, on top of her pair of jeans. The bastard! He’s putting her all in.

“You _bastard_ ,” she breathes.

“Put up or shut up, Case,” he says, his voice still strained, his eyes still darker then normal, his pupils huge in the dim light. She wonders suddenly if he’s got another erection, and, whoa, where did THAT thought come from?!

But… he’d ended up with a boner just playing a game of Twister a couple weeks ago and, like, touching her leg. That’s practically Victorian. And she’s a mess of horrifying, squirming feelings, her nipples throbbing, just _sitting_ here. Derek has to be feeling the same way. He _has_ to be.

She looks over at him, wearing cargo pants, his naked shoulders hunched inward slightly. She can see faint goosebumps on his arms.

Then she lets her eyes drift upward to the staircase and freezes, sucking in her breath.

Derek’s eyes widen, and he snaps his head around as well. As soon as he turns away, she grabs the ace from underneath her thigh and swaps it out for the five of clubs in her hand, shoving the five into the crack under the table where the wood goes around the bottom curve of the surface.

She looks back up at the stairs and blows her breath out sharply. “I thought I heard something,” she says, making her voice soft.

Derek turns back around, eyes starting to narrow. Before he can put two and two together she tosses out the last of her chips. So yeah. Apparently she’s all in now.

“Ready?” she asks. God, she hopes she gets her pants back.

He hesitates, then nods. “Count of three?”

“Okay.”

“One… two… three.”

She turns over her two red aces, confident, and then looks across at Derek’s hand.

Which…

Derek’s gapes at her hand, and then his eyes slide back up to her and he gasps, loudly, “You…!”

“You CHEATER!” she yells, and jumps up, pointing a finger at his hand, where Derek _also_ has a pair of red aces. “You cheated!”

“ _You_ cheated!” he yells back, and points at her own hand, an exact match of the one in front of him.

“I….” _think quick, Casey, c’mon, there has to be a good explanation for this_ , “…did not!”

“You…!”

“ _You_ …!”

“Everything okay up there?” a sleepy voice comes from the kitchen, echoing up faintly from the stairway to the basement. George’s voice! Oh fuck oh _fuck_.

Derek tosses her jeans at her so fast she almost doesn’t see him move. She starts to pull them frantically on as he yanks his t-shirt back on over his head. Derek grabs the cards from the table and stuffs them in his back pocket.

“Everything’s fine!” she yells back to George, bringing the volume down a notch, and mimes at Derek to throw her his hoodie. “Derek and I were… watching a movie.” She gets both arms through the hoodie and zips it all the way up the front, hiding Derek’s jersey underneath.

There’s the muffled sound of a yawn, then, “Must’ve been an exciting one.”

“So many guns,” Casey says. “Uh, explosions. Killing people? You know. Boom.”

“Well, go to bed, you two. It’s past both of your bedtimes.”

“Will do,” she says, trying to sound upbeat and not, like, 100% panicking. She shoves her necklace and earrings into the pocket of the hoodie.

“Night, Dad!” Derek calls out, but his voice cracks in the middle of saying it, and for one awful second Casey is sure George is going to hear that ominous crack and correctly attribute it to technically-probably-illegal stepsibling card games that accidentally ended up involving light stripping/clothing removal ( _accidentally_!). But there’s no answer, and Casey’s already halfway up the stairs anyway, Derek right on her heels.

They practically run to Derek’s door, where he puts his hand on the knob to head in, and she can’t help it, she whirls around one last time to whisper-shout at him, “You _cheat_ , Derek.”

She slams the door to her bedroom room closed after her, heart pounding in her chest.


	4. Second Intermission

**Notes for the Chapter:**

> Thank you to htbthomas for beta reading this chapter again for me!

Casey only comes down for breakfast the next morning after she’s sure that Derek has left. She grabs a bowl of cereal, the milk from the fridge, and plants herself firmly at the kitchen island to think.

Because: What. The hell. Was THAT?

She can’t even think about the previous night without feeling like her stomach is slowly tying itself up in knots and she either wants to melt down with frustration or die of complete and utter embarrassment. What were they _thinking_? She can hardly reconcile the idea that last night she’d ended up basically _stripping_ in front of Derek with the fact that she’s here now, eating breakfast, about to go to school, wearing all of her clothes, thank you very much, just like normal.

Casey stares at the sugar container on the counter and slowly chews her cereal.

—

“Casey? ….Casey. Earth to Casey!” Emily grabs her shoulder and shakes, snapping fingers in front of Casey’s face.

“What?”

“I said, are you coming to the game tonight?”

“Oh.” She tries to imagine watching Derek play hockey that evening, and she can feel her face heat up just thinking about it. “Probably not.”

“Why not?”

“Homework?” Casey tries.

Emily groans. “Homework. On a Friday night. Really, Casey?”

“Don’t be jealous, Em,” she says, and walks with Emily away from their lockers. “Besides, I hardly ever go to the games. Why would I go to this one?”

Emily pulls her books in closer to her chest. “Because you said last week that you were thinking about going and Sheldon is going to be there and… oh, hey, Der -“ Emily takes a couple fast steps ahead of Casey in the hallway, and pulls Derek out from behind a gaggle of grade nine girls like a magician producing a rabbit out from a hat. Casey stops in her tracks. Derek’s eyes fly to her face and there’s a flicker of _something_ before he smoothes his expression out and Derek is swaggering his way in front of her, like it’s any other day.

“Tell Casey she should go to the hockey game with me tonight,” Emily says, and pushes Derek in her direction.

“You should come to the game tonight, Case,” Derek repeats obediently, his tone a mockery of a real request, and suddenly all of Casey’s nervousness downshifts straight into anger. Seriously, Derek is such a _jerk_!

“See?” Emily says. “You should come.”

Casey crosses her arms over her chest. “Why, so I can watch Derek cheat at hockey the same way he cheats at everything else?”

Emily’s jaw drops.

Derek takes a step closer to her in the hallway. “I don’t _cheat_ at hockey, Casey.”

“Oh, no? Just everything else then.”

“You should talk.”

Casey puts her nose only a couple inches away from his and glares. “Try me.”

“Um,” Emily says, looking back and forth between the two of them with increasing alarm, “what is going on with you two?”

Derek blinks, then backs away a step again before muttering, “Nothing.”

“You don’t have to go to the hockey game with me, Casey,” Emily says, still sounding a bit stunned. “I mean, I didn’t know you wanted to get out of it that badly.”

“It’s not you, it’s just - you know how Derek and I are.” Casey laughs, but it sounds hollow, even to her.

“Yeah, but…”

“You heard the keener, she doesn’t want to go to the hockey game.” Derek looks back at Emily, then rolls his eyes pointedly in Casey’s direction, twirling a finger around his ear.

Casey shoves Derek on his shoulder. “Stop it.”

“Gee, only ‘cause you asked so nicely, _sis_ ,” he responds without thought, leaning sarcastically into the last word.

They both blanch at the same time, and finally fall silent.

“ _Well_ ,” Emily says, wide-eyed, “this is fun.”

—

She’s doing homework after school in her bedroom that night (see, she has real homework to do! it’s not an excuse at all!) when she hears a knock at her door. She says “Come in” before she thinks about it.

Derek sticks his head in, and Casey drops her pencil on a page of half-done math equations in shock.

“Hey,” he says, and slides himself the rest of the way through her door. “I…” He clears his throat. “So I know you made it very clear that you’re not coming to the game tonight, but I do still, um, need my jersey back.”

She stares at him.

“For me,” he adds quickly, apparently feeling the whole concept needs further clarification.

All she can see in her hamper is the worn t-shirts and her bra from yesterday and a crumpled-up pair of underwear she has to dig through to get to Derek’s jersey, which she’d thrown in her own laundry without really thinking through the fact that she’d need to, you know, actually give it back to Derek at some point. She shakes the jersey out, praying there’s nothing stuck to it where she can’t see. She tries not to remember that she’d worn it in front of Derek wearing nothing but a glare and the unvarnished determination to beat him at his own game less than twenty-four hours ago.

“Good as new!” she says brightly, to cover her own twisted-up nerves. She holds it out to him, and he takes a couple steps into her room to take it from her. She expects him to hightail it out of there as as soon as possible, but instead he just stands like a dork near the end of her bed, gripping the jersey around in his fist.

Derek shuffles his feet, and finally says, “Look, I’m s-sorry I was a jerk to you earlier today.”

Casey blinks. Is Derek… apologizing?

Derek takes a deep breath and continues, only stuttering a little bit. “I’ve been… I just… I am sorry.”

Holy crap, it _is_ an apology. An actual apology! From Derek Couldn’t-Talk-About-My-Emotions-If-I-Tried Venturi. Casey looks around wildly, pretty sure the earth is about to end, that the floor is going to crumble away underneath them and zombies or something are about to break down the door.

When a couple long seconds pass and the entire house doesn’t fall down around her ears, she realizes that Derek is staring at her expectantly now.

“What?”

Derek presses his lips together, look faintly hurt, of all things. Ugh. One of the worst things about Derek is how, sometimes, he’s _not_ the worst guy in the world. 

She sighs. “Fine. I mean, I guess I’m sorry too. I know you don’t cheat at hockey.”

“Thank you.”

“…Mostly because the sport has referees who impose penalties on you if you do try to cheat, but that’s beside the point.”

“Fair enough.”

Derek pauses again and Casey wonders, with a crazy spike of fear and adrenaline, if this new version of Derek who’s into sharing and caring is going to try to talk about what happened last night. She literally cannot think of a worse idea, she’s pretty sure they should go to their graves never talking about their whole weird strip poker deal ever again, she needs to think of -

Wait. The _date_. Derek said he had a date! With a girl he isn’t related to! Casey grabs onto the thought like a lifeline.

“So when’s the date with the girl you wanted the Prince for? Wasn’t that tomorrow?”

He eyes twist back away from her and he shrugs, clutching the jersey tighter again. “Oh. We decided to, um, call it off.”

Oh _no_.

She makes herself sound scornful, fights the very idea that Derek calling off a date is anything other than a sheer and utter coincidence. “So she came to her senses, huh?”

“I guess. It’s not a big deal.”

“Yeah, not a big deal to the person who got _du-umped_.”

“Shut up, Casey.”

“Dumped,” she repeats, trying not to sound like she’s totally panicking.

“You are so annoying,” he says, turning to leave ( _finally_ ), but his mouth quirks up when he says it this time, sort of teasingly fond. She stares at his bottom lip for much longer than she’s pretty sure she’s supposed to as he closes the door behind him.

Oh _god_.

She is so screwed.

—

She lays in bed that night after Derek gets back from the game, staring at her ceiling, and she can’t stop thinking about it.

She wants to make out with Derek.

…She wants to make out with _Derek_?!

And it’s disgusting, because Derek is a) hellbent on usually doing nothing more with his life than ruin her own, b) a chauvinist pig, and c) sort of related to her, in a probably important legal sense. Also, Derek is smug and insufferable in general. He’d probably lord it over her for months if he knew she was even thinking about what it would be like to kiss him. She can just imagine the taunting she’d be in for, and the thought makes her want to lock the door to her room, crawl under her bed, and never come out again.

But…

 _We’re not actually related_.

She pulls the covers up higher around her shoulders.

She can hear the low sound of music through the wall connecting her and Derek’s bedrooms, half-heard lyrics only audible by the vent near the base of her bedside table. Maybe he’s sprawled out on top of his own bed, knees bent, idly flipping through a magazine, or at his computer, slouched and staring at the screen. She can imagine the look on his face, the slack expression, the oddly serious way he tilts his head when he isn’t interacting with other people, when it’s just him.

Casey flips over onto her stomach and stares at the wall behind her headboard.

Would it really be so bad if she kissed him? It’s not like it’s that big a deal to just _kiss_ somebody; it’s not like they’re ever going to get married or anybody would even have to know ( _ever_ ). They could just be people who made out that one time when nobody else was around, and who never discuss it with another living soul for the rest of their lives. That’s a thing, right? Like the non-fucking, stepsibling equivalent of fuckbuddies. They could be… make out step-pals.

Casey buries her face in her pillow and groans.

 _Doomed_.

—

She’s cranky and exhausted the whole next day, and collapses on the couch after dinner, grabbing the remote. TV therapy is just what the doctor ordered.

She watches some sitcom with a canned laugh track for a while with Lizzie, until Lizzie wanders off and Derek wanders in. Derek sprawls back on his recliner, a respectable nearly-all-of-the-couch-and-an-additional-chair between them, as all the rules of decency and stepsibling-hood intended. She tries not to look at him. The idea that she’s even considered what it would be like to kiss him is deeply weird, it’s driving her crazy, it’s bonkers, it’s a sure sign that her life is spiraling off into the deep end.

“Why are you watching this?” Derek asks finally.

Casey doesn’t answer. What, she doesn’t have to defend her life choices.

“Is it because you enjoy things that aren’t funny?” Derek’s quiet another minute or so, and then, naggingly: “You know, there’s a hockey game starting in…”

“I don’t care.”

“But it’s the…”

The audience in the sitcom breaks into uproarious studio laughter.

He sighs. “You leave me no choice, Casey.”

“No choice what?” she asks, not really sure what he’s saying.

Derek lunges at her, across the armrest of the couch, grabbing for the remote, and the shock of him trying any sort of move that involves actual potential contact with her surprises her more than anything else. She fumbles the remote at her side, and the next thing she knows Derek has it clutched in his fist, dancing away from her across the living room.

“Derek, you _ass_! Give that back to me.”

“Nuh uh,” he says, and aims the remote at the TV behind his back, changing the channel to the pre-game show. “Finders keepers, losers weepers.”

“Oh my god, what are you, _twelve_?”

“ _Oh my god_ ,” he parrots back. “What are you, a pre-teen Valley girl?”

“Give it. Back. To me,” she grits out. 

“Make me,” he says hotly, like he’s actually challenging her to a fight or something. Except Derek doesn’t sound as mean as he did yesterday; he’s got a look in his eye like he does when he’s spoiling for a good argument, like he wants her to argue back.

“What’s gotten into you?”

“Oh, hey, hockey,” Edwin says, stampeding his way down the stairs like a herd of elephants, and throws himself on the couch next to Casey. “Sweet.”

“Edwin’s into it,” Derek says, giving her a pointed look, like Edwin’s opinion on a sport he knows his older brother idolizes should sway her own opinion somehow.

“Oh, well, if _Edwin_ is into it…”

“Exactly,” Derek agrees.

Casey crosses her arms over her chest. “Fine. We’ll watch hockey.”

“…Really?”

“You want to watch hockey, let’s watch some hockey, big shot.”

“Who are you and what have you done with Casey?”

Casey shrugs.

“C’mon Derek,” Edwin says. “The game’s starting.”

Derek sits back down in his battered old recliner, clutching the remote suspiciously.

—

Casey tries to watch the game, she really does (well, sort of), but the steady drone of the announcers and the background noise of the game, the crowd and the swish of metal over ice, slip over her like a warm blanket and before she knows it she wakes up with her head on Edwin’s shoulder.

“Casey,” Edwin says, shoving her away from him, “if you’re going to snore, at least snore on the other side of the couch and not directly into my ear.”

“Shurh,” she agrees, and pulls her knees up underneath her on the couch and drops her head on the armrest. She falls asleep again instantly.

—

When she wakes up the second time it’s dark outside. The hockey game must have ended at some point because there’s an old action movie on the TV now, featuring some roided-up dude from the 80s with a bandana around his forehead lighting up an army of extras all pretending to die theatrically. The volume is so low she can barely hear the tat-tat-tat of the fake machine gun.

The light from the television flickers eerily in the dim room. Casey can hear Marti shrieking happily upstairs and the distant sounds of bath time splashing.

Casey lets her eyes close again and burrows down into the blanket that somebody must have thrown on top of her at some point. She’s warm and comfortable and about to drift off again when she feels the brush of _something_ against her ankle.

She glances down toward her feet and is surprised to find Derek slumped on the far end of the couch where Edwin had been. The blanket on top of her is also covering him, the big afghan draped over his legs also tucked up around her own shoulders.

And Derek, she realizes slowly, has her feet in his lap.

Derek’s staring at the movie on the TV, muted guerrilla fighters sneaking through the rainforest with black streaked across their eyes. She can feel his fingers now against the skin of her bare feet, hot where they’re cupped around the ball of her foot. A missile wipes out a poor defenseless palm tree in the jungle and the muscles of his hand flex involuntarily against her instep.

Because… Derek is holding her feet.

Um.

The whole thing feels surreal and _weird_ , like that dream Casey had a couple nights ago where Ryan Gosling was her substitute algebra teacher and had told her he’d never seen anybody solve an algebra equation as beautifully as she did. Because the idea of somebody like Derek holding her feet in his lap while she sleeps almost certainly only exists in a universe where Ryan Gosling also teaches substitute math in his Canadian hometown a couple times a semester.

She doesn’t do anything. She just closes her eyes again, stays where she is. Keeps breathing evenly.

You know, normal stuff. Totally normal.

But after a few minutes, she gets the idea that maybe Derek figured out that she woke up at some point. He’s still staring at the TV, but there’s a forced quality to his attention now. She can almost feel him very carefully Not Looking At Her.

Underneath the blanket, his fingers start to trace the side of her arch.

Casey stops breathing.

The blunt pad of his thumb slides around the ball of her foot, and slips up her ankle. He palms her achilles tendon, wraps his fingers there, and his hand feels warm and weirdly large against the back of her foot.

Her heart is tripping over itself; she shifts unconsciously, slipping one foot on top of the other in his lap. He’s got to know she’s awake now. Somehow Casey can’t seem to care over the roar in her head.

Derek’s fingers move to trace her ankle bone in a slow circle.

Oh god oh _god_. This is actually happening! She can feel the same dark thickness in the air as when she’d stripped when playing poker, when he’d looked at her for that one split second with…

“Hey, Casey,” Nora says, sweeping down the stairway and making both of them jump, making Derek’s hand convulse against her ankle, “can you come up and look at Lizzie’s homework? She’s freaking out about getting something wrong and I can’t deal with her and Marti at the same time right now.”

Nora waves at them and leaves the room as fast as she’d entered, beelining it toward the laundry room.

Very carefully, without a word, Derek unwraps his fingers from her foot.

Casey feels overheated and ashamed, like her mom just caught her and Derek full on going at it on the couch, totally naked. Never mind that there’s a blanket (a totally decent, respectable blanket) over both of them, they are both very much fully dressed, and the worst thing that _had_ been going on was an awkward bout of stepbrother/stepsister-style foot holding.

 _Foot holding_.

Right.

What the FUCK.

“ _Now_ , please, Casey,” her mom trills, blowing through the dining room again on her way back upstairs. Casey sits up finally, the blanket slipping off her shoulders as she steps past the couch. She feels dizzy, the blood rushing to her head, the pulse in the core of her body overwhelming.

Derek is back to staring at the TV again, the afghan over his lap and his lips parted, breathing hard as he watches some second string Rambo blow up a small hut somewhere in the jungle.

Casey swallows, and follows her mom upstairs.


	5. Drinking Game

Casey’s brushing her teeth when Derek slides in next to her, hogs all the mirror space, and starts to floss.

They don’t talk, but Casey is acutely aware of Derek standing shoulder-to-shoulder with her, flossing like he doesn’t have a care in the world. She seems to have developed a proximity alert to Derek’s presence in the last week or so, her body going hot and uncomfortable when he’s close to her, like she’s allergic to anything Derek Venturi. He’s moved on to brushing by the time she spits and rinses, her mouth minty and clean.

She’s turning to leave when Derek reaches for her wrist. He drops his hand quickly, holding up a finger in a wait-a-sec gesture. Casey can feel the skin where he touched her crawl with sudden goosebumps. She rubs her elbows with the palms of her opposite hands.

Derek finishes brushing his teeth and spits into the sink, then turns toward her and asks, “What are you doing this weekend?”

“Not much. Studying with Em on Sunday. Maybe going to the mall sometime.”

“Good, because I have something for you.”

Um.

“So do you want to hang out? Maybe Saturday, after the sibs go to bed?” Derek continues, seemingly unaware of her sudden, frozen consternation.

“We have to hang out because you… have something for me.”

Derek nods. “Exactly.”

“I… okay?”

“Awesome,” Derek says, and leaves her standing in the bathroom, wondering what on earth she just agreed to.

—

Derek plays dumb until Saturday after dinner, when he pulls her into the garage, and then, instead of both of them getting into the Prince like she had assumed was going to happen at this point, pulls out a six-pack of Keystone from the trunk of the car with a gleeful grin.

“What,” she says.

“It’s for you.” Like giving a teenage girl who also happens to be his stepsister a six-pack of the cheapest beer possible as a gift is something to be legitimately proud of.

“ _What_ ,” she says.

Derek jumps up on the hood of the Prince and cracks open one of the beers, crossing his feet at the ankle.

“What if somebody catches you?” she hisses, looking around wildly, like George and Nora are going to jump out from behind the hockey net stored in the corner. “And how on earth did you get _beer_?”

“I’ve got my ways,” he says, loftily.

Casey holds up a hand. “You know, I really don’t want to know.”

“I just - I thought we could, you know, hang out or something. Get things back to normal.”

She eyes the entire scenario dubiously. “And you think _this_ is normal?”

“C’mon, Caseface.” Derek pats the hood next to him. “I saved you a spot.”

“Wow, a hard metal surface to sit on? You shouldn’t have.”

“I know.”

She considers crawling up across the hood to the spot on her hands and knees, but the idea seems weird she can’t completely put her finger on, so she tries hopping backwards up onto the hood instead. She lands on her ass with her legs sticking out straight in front of her off the front of the car like a kid’s, several feet away from her goal. It’s way undignified. She wiggle-crawls backwards on her butt a couple feet like a malfunctioning spider, finally ending up next to Derek, who solemnly hands her a beer in what she can only assume is a spirit of celebration for her even making it up on this stupid hood. Awesome.

She cracks the tab, takes a sip, and grimaces. Nope, beer didn’t magically become awesome since the last time she tried it!

Derek notices her look of distaste. “That good, eh?”

“Better,” she says. “Mmmmmm.”

“You’re not going to drink that beer, are you.”

“I might!”

Casey takes a second small, defiant sip from the can, just to prove him wrong.

—

Casey’s kicking her heels against the hood of the car and wondering what, exactly, Derek thinks the two of them are doing. Is this a Derek-style apology? Or Derek’s idea of a great Saturday night, hanging out with his keener stepsister, drinking lukewarm beer? Nothing about this makes any sense.

“You know what we need?” Derek asks, like he can tell Casey is thinking pretty seriously about giving up on the whole pretending-to-drink-the-shitty-beer-she’s-holding thing. “A _drinking game_.”

“Oh, no. No way.” That is the worst idea Casey can think of.

“C’mon, it’ll be fun. I know a good one we can do, too. It’s really easy.”

“I don’t know about this.”

“Hear me out, at least.”

Casey sighs. “Fine. What’s it’s called?”

“Well, this game doesn’t really have a name.”

“Um, okay. How do you play?”

“The rules of the game,” Derek says proudly, “are that we make the rules up as we go along.”

Fan-freaking-tastic. “It sounds like you’re making this entire thing up.”

“Cross my heart and hope to die. Swear to god, it’s a real game, Case. Sam taught it to me.”

“Riiiight,” she says. “Because Sam totally taught you the game with no name and no rules.”

“Exactly. Well, sort of. I mean, there is one rule: when the game starts each of us gets to make up a rule for the other person. And then, after that, every time you break a rule you take a sip of your drink, and then the other person makes up an additional rule that you have to follow. Like - let’s say my rule for you is that you have to sing every time you ask me a question.”

“Okay.”

“Hey, Casey. Knock, knock.”

“Who’s there?” she says, evenly.

“See, you asked me a question and you didn’t sing it, so you drink. And then I get to make up a new rule for you, in addition to whatever other rules you’re already following. Got it?”

Casey takes a swig from the can of beer, making a face, and Derek whoops in appreciation.

She rolls her eyes. “Fine,” she says. “Let’s do this.”

—

“So my first rule,” Derek says slowly, mulling it over before grinning, “is that whenever you say my name you can’t just call me Derek, you have to call me… Derek the Awesomest.”

“Derek the Awesomest?”

“Yup.”

“Seriously?”

“Seriously.”

“This is so dumb.”

“Rules are rules,” he says. “And don’t tell me you’re not a huge, brown-noser fan of following the rules, Casey.”

“ _So dumb_.”

“Maybe. What’s your rule, genius?”

“Hmm.” What can she have him do? What does he do that annoys her the most? “You… you can only call me Casey. None of those stupid little names that you think you’re so clever for coming up with. Keener, Princess, Space Case, Klutzilla - none of that.”

“You don’t like Princess? I thought all girls were into being princesses.” Derek mulls it over, swishing beer in his can. “Am I allowed to call you Case?”

“Nope.”

“That’s cruel.”

“A wise man once told me that rules are rules.”

“I guess I can’t argue with that.”

“Game on, then.”

And then they stare at each other.

Silently.

It’s quiet in the garage without the normal bustle of the house, Lizzie and Marti and Edwin stomping around and screaming and hockey being played in the hallways upstairs and the TV on in the living room, and George and Nora running around frantically in the middle of it all, trying to keep it together.

Somewhere, a lonely cricket chirps.

“Well this is fun,” Casey says, setting her chin in her hand.

Derek leans back, propping his elbows up on the hood of the car. “That’s because this is a game you’re supposed to play while you’re just hanging out and talking. You know, acting like normal people do? Drinking, having fun, all those things that regular teenagers do. You might have heard about that.”

“Well, then, give us a topic to talk about.”

“A topic? What is this, debate club?”

“Let’s talk about…“ _how you got an erection when we were playing twister, how we accidentally ended up playing strip poker that one time_ , “…um, school?”

Derek groans, his head falling back.

“Study techniques?” she continues, warming up to the idea. She loves homework talk! “Flashcard making tips? Highlighting strategies? Top ten homework do’s and don’ts?”

“Shoot me now.”

Casey huffs. “Fine. I don’t hear any of your brilliant suggestions.”

“Hockey,” Derek says promptly. “How great I am at playing hockey. Other things about hockey.”

She fake-gags, sticking a finger in her mouth.

Then she thinks of another, _brilliant_ suggestion.

“Sex,” Casey says, kind of fast, trying to get the word out before she chickens out on the joke. “Sex stuff. Sex sex sex sex sex.”

Derek chokes on his tongue, then starts to sputter. Casey keeps it together for maybe a solid two seconds before cracking up.

“Oh my god, you should see your face,” she gasps, folding over herself in laughter. “Classic.”

Derek opens and closes his mouth a couple times before starting to grin back to her. The red staining his cheeks begins to fade almost as soon as she notices it.

“Didn’t think you had it in you, Case,” he says, already retreating back into his normal smirk. “So we’re talking about sex now, huh?”

“That’s what I said, didn’t I?” she responds, trying not to ruin her uber-cool casual-joking-about-sex-like-an-adult-with-Derek! vibe. Then she re-thinks what he just said, and stabs a finger at his thigh. “And ha! You said my name wrong. Drink up, loser.”

“I know I did,” Derek says, still grinning, and takes a long swig of his beer. “Somebody had to man up and get this party started. Also, that makes us even after you took the hit on the demonstration we did about how this whole thing works.”

“And I get to come up with another rule for you,” Casey says, pleased. “Let me think.”

“Don’t sprain anything.”

She leans back on her own elbows, staring up at the exposed metal of the garage ceiling, the wooden rafters criss-crossing over top of them like a cathedral. There’s some fishing poles Casey can’t imagine George ever using and a couple old wooden boards stored up there, lying parallel over top of them. 

“My second rule for you,” she says, “is that you have to keep your left hand on the hood of the car at all times.”

Derek presses his palm down next to his hip, and she grins.

—

“Hey Casey. Knock, knock.”

“Are we really doing this again?”

“Knock. _Knock._ ”

“Fine. Who’s there.”

“Derek.”

“Derek who?”

“Derek the Awesomest says drink!”

It’s so embarrassing, she can’t believe she fell for _that_.

—

The MEGA-PENALTY happens entirely by accident.

It starts with Derek calling her _Case_ , the name rolling off his tongue before he can catch himself, and then somewhere in the ensuing argument Casey slips up and screeches out a two syllable _Der-ek!_ , which makes Derek laugh so hard he has to fling both hands out to keep from slipping sideways off the hood of the car, breaking his left-hand-on-the-Prince rule, which causes Casey to break her stop-rolling-your-eyes-at-me rule (Derek’s third for her) while simultaneously Derek messes up the what-if-you-weren’t-such-a-dick-all-the-time rule (her fourth for him), and the whole thing devolves from there.

They’re trying to sort out penalty drinks when Derek suggests they drop new rules for this round in exchange for doing a shot instead of drinking to get them both back to square one.

“Unless you’ve got a bottle hidden somewhere I don’t know about,” she says, “I don’t see how that’s an option.”

He grins, slyly. “I think I know where we can get one.”

Her jaw drops. “No way.”

“Yes way.”

“Wouldn’t they notice?”

“Nah,” he says, and jumps off the hood of the car. “They won’t miss a couple shots, that’s barely anything.”

What the hell. She’s almost done with her first beer and feeling a little buzzed. She’s having a surprisingly good time. Who says she can’t live dangerously once in a while? “Mega-penalty!” she agrees, raising up her beer, and jumps down next to Derek.

They sneak into the house, trying to keep their voices quiet. They can hear the muffled chatter of George and Nora’s small TV downstairs, and the occasional burst of laughter from the basement. Derek pulls out the bottle of vodka from the freezer, yanking it out from between an expired bag of frozen green beans and a sad frozen pizza strapped to a greasy sheet of saran-wrapped cardboard.

“I think I’ve seen a shot glass around here somewhere,” she whispers, looking around.

She digs in the back of drawers until she unearths a single shot glass that says NIAGARA FALLS with a red maple leaf embossed underneath the words. Casey thinks it seems much cooler to do a shot out of the actual shot glass, but Derek insists they have to do it at the same time (“for _solidarity_ ”) so they pull two orange juice glasses out of the dishwasher instead and carry them back out to the garage along with the vodka and the shot glass.

Casey jumps back up on the hood of the car, then carefully measures out full shots of vodka and tips one into each of the juice glasses. The vodka looks like a little pool of water in the cups, a deceptively small amount of something harmless.

“I can’t believe I’m going to do an actual shot,” she says. “This is crazy.”

“Don’t wuss out now.”

“You wish.”

“Actually,” Derek says, sitting down again next to her on the Prince, “I don’t. I mean, Casey McDonald, doing shots? Nobody is ever going to believe me.”

“Don’t you dare tell anybody about this.”

“Like I just said, nobody is going to believe me anyway.” When he says it that way, it sounds sort of nice. Like he’s not just baiting her so he can go blab all over the school about how he got Casey McDonald, Keener Extraordinaire, drunk that one time.

“Right. Here you go,” she says, and hands one of the glasses to Derek.

“Bottom’s up.”

“Cheers,” she says, and follows Derek’s lead, tipping the liquid back into her mouth.

It is _disgusting_.

Oh god, it is the most awful thing she can think of! She almost gags, and some sort of instinct that says _get rid of this NOW_ kicks in right as she remembers that she doesn’t want to spit out a bunch of vodka in front of Derek (because she will _never_ live that down) and swallows fast instead. The alcohol burns like acid in her throat. She just about manages to get the last of it down before she starts coughing.

“That was _terrible_!” she gasps.

Derek is flushed up bright red and his eyes have a suspicious shine of wetness.

“Mmm,” he manages to croak out.

“You’re such a liar,” she coughs, right before Derek starts coughing as well. Sweet vindication!

The awfulness in her throat lessens as the initial gasping burn slowly transitions into a strange warmth. She can feel as the vodka slips its way downward, radiating heat, like a star sinking into her body. It reminds her of the way it feels to drink hot cocoa after coming in from the cold in the winter, the warmth spreading outward into her chest from a foreign source. It’s actually kind of nice after a while.

—

“Am I supposed to be touching my nose right now?” Casey frowns, and puts her pinkie next to her nose just in case. It’s so hard to remember!

Derek squints at her. “Maybe?”

“I forget if I’m supposed to touch my nose for… um, calling George ‘George’ instead of ‘Dad’… which is super weird, by the way, or… or something else?”

“I thought you had to stick out your tongue when you did that?’

“I don’t know! We should have kept a list, Derek. Then we’d know for sure.” She sighs, dreamily. “Lists are amazing.”

“Pen-al-ty,” Derek says. “You said Derek. I _can_ remember that one.”

“Boo,” she says, and drinks.

“What to do, what to do.”

Casey waves a hand. “Take as long as you want.”

“What are we at, a zillion rules?”

“I think so?”

“Then my next rule for you,” Derek continues, like he’s half about to make a joke and half some grand proclamation, “for a zillion plus one, is that you can’t kiss me.”

It doesn’t even register for a minute. There’s no way Derek knows she’s been thinking about him like that. And besides, this is all on HIM, anyway. Derek’s been the one getting awkward boners all over the place and touching her feet with _intent_ and being all weird just because she happened to wear his jersey for a harmless game of poker. This is totally on him!

She must have been gaping, because he continues, “You heard me, Casey: no kissing, no tonsil hockey, no first base, no matter how much you know you want to.” Derek sticks his tongue out and wiggles it around in her direction, smirking and sort of smiling.

Of all the smug, _presumptuous_ …!

She makes herself laugh scornfully, although she dimly thinks it might sound wild and nervous more than anything else. “Why would I _ever_ be kissing you? Did I accidentally trip and land on your mouth? Because that’s the only scenario I can think of that makes any sense.”

“Well, they don’t call you Klutzilla for nothing.” 

“ _You_. _You_ call me Klutzilla.”

“Uh, that’s because it’s an amazing nickname. Klutzilla,” Derek says, rolling the word around in his mouth with obvious relish. He mimes walking two fingers down his forearm, then has his finger-person trip over his knuckles and splatter against his palm, and snickers to himself. “See? Hilarious.”

“Laughing at your own joke does not mean something is funny, Derek! Derek the Awesomest,” she amends quickly.

“Only if you have a sense of humor.”

“I wouldn’t kiss you if you were the last person on earth,” she says, crossing her arms over her chest and painfully aware of how VERY MUCH she is lying. Her face feels like it’s on fire. “And you didn’t need to make something a rule when it’s already a fundamental law of nature. Like gravity. Or like the moon not making out with the sun.” There’s something important she’s forgetting here. What is it? Oh, right! “Also, drink. You called me Klutzilla.”

Derek clinks his can against her own, still snickering, before complying.

“And I get to make another rule for you now too.” What the hell, she’s not going to let him put this solely on her. “My rule for you is that you can’t kiss me either.”

“Sold,” Derek says.

Then he _winks_ at her.

“You’re the worst,” she says, ignoring a tight, giddy nervousness threatening to spill out from her brain and drown out all the reasons this is a terrible, terrible idea. She knows that people get drunk sometimes to give themselves an excuse to do things they wouldn’t normally do, but that is NOT what her and Derek are doing here. This is a totally normal, teenage-appropriate hang-out between ~~friends~~ stepsiblings! There’s nothing weird happening here!

“Just as long as you don’t kiss me first, we’re cool,” he says, mockingly.

Casey takes another drink, unprompted, just to give her hands something to do.

—

“And so I said to George, that isn’t Edwin’s _ping pong_ racket,” Derek says, and Casey doubles over with laughter, unable to stop from cracking up even if she wanted to, her mind hazy and giddy and warm.

“You did not!”

“Swear to god.”

“I can’t believe I’ve never heard that story before.”

“That’s my best blackmail material on Edwin. I can’t go around telling it to just anybody.”

“I’ll use it wisely, D,” she promises.

“You better. And drink,” he says, pointing at her. “You said my awesome, awesome name wrong.”

Casey gasps. “I did not say Der- _your name_. I said D. You said I only had to say Derek the Awesomest when I said- you know. There was no rule about any other names.”

“Technicalities, schmecknicalities.”

“Following rules is all about the technicalities. Although…” She eyes the bottle of vodka, sitting on a workbench in front of them, “do you think George and Nora would notice two more shots missing?”

Derek flashes her a wide grin. “I like the way you think, Spacey.”

“I revoke my previous rule about you having to have your hand on the Prince at all times, so that you can go get us the bottle.”

“Win win,” Derek says, and hops off the hood of the car.

—

Derek’s eyes are a little glassy, focused and unfocused at the same time. He’s laughing a lot, his face scrunched all up, and it’s weirdly appealing, like he’s forgotten to hide behind the layer of douche-y smartass armor he normally hauls around. Casey is starting to understand why people like drinking. She’s never understood the appeal of getting drunk before, but this - this is a version of Derek she’s only seen in bits and pieces, when he’s giggling and messing around with Marti or when he’s serious for a rare moment with her. This is, like, the inner-Derek. A Derek with his defenses down, loose and sloppy and sort of stupid.

“You loser,” she says affectionately, and shoves Derek on his shoulders. He’s sitting cross-legged on the hood of the car now, facing her. He slaps a hand back and then shakes his head at her.

“Tsk, tsk, Case.”

“ _Drink_! “ she shouts. “Drink, drink up, you said it again.”

Derek blinks solemnly and with way too much effort at serious thought. “Isn’t that your name?”

“Case- _y_.”

Derek presses his lips together and frowns. “I don’t think that’s right.”

“You can’t even help yourself, Der - Derek. Derek the Awesomeness. Awesomest.”

“Never gets old,” Derek says, and toasts her before drinking. Casey swings her legs up to cross-legged as well. Derek’s left knee is right by her own like this. His knee is sort of knobby-looking, she thinks, like a door handle that also has hair growing out of it.

“Your knee is all hairy,” she says, frowning.

“I’ve got news for you, Casey: both of my knees are hairy. Because I have two knees.”

She flicks a bit of the leg hair that’s sticking up from his skin. “Boy’s legs are so weird. Your knee is so,” she pokes at it, trying to find the right word, “ _bony_. And hairy.”

Derek watches her hand jab at him. “Hate to break it to you, but pretty sure yours is too. Well, not the hairy part.”

“My knee?”

He nods.

“Bony?”

“Yeah.”

She lets her fingers drift up from his knee to his elbow, giving it a good solid poke as well, then further up, brushing against his jawline. It’s so easy when the two of them are already half-leaning in toward each other. She doesn’t even think about it.

Derek freezes.

There’s a soft prickliness on his cheeks, in the indentation under his jaw. She knows he shaves sometimes in the mornings - every other day, maybe - but she’s never really thought about the reason why. His facial hair is a dark blond and spotty in places, a little lighter than the sandy brown on his head, and almost invisible when cropped so close. She can feel it with her fingers, but wouldn’t have noticed it if she wasn’t looking for it.

“You have facial hair,” she says, and immediately feels dumb (because of course Derek knows he has facial hair, that’s why he shaves, duh).

She half expects him to say something sarcastic back but instead he hesitates, and then nods.

She traces the pad of her thumb against his jawline, following the curve of bone underneath skin. Derek’s five o’clock shadow reminds her of the brush with stubby plastic bristles they use to scrub dishes in the kitchen. It’s soft and scratchy at the same time, sort of pleasantly raspy. It feels nice. It feels really -

Wait.

Wait! What is she _doing_? What is this? Is this some kind of a trick she’s been lured into by an uncharacteristically passive Derek Venturi? What is happening here?

She drops her hand, suddenly and horribly self-conscious.

“You,” Derek says, his voice raspy in a way that makes Casey prickle with uncomfortable heat, “you don’t have to stop.”

“When did you start shaving?” she asks instead. Her hand, where she touched Derek, feels like it’s buzzing. Her whole body feels like it’s buzzing. She feels like a buzzing, glowing, wired-up lightbulb, lit from head to toe. It’s ~~probably~~ definitely the alcohol. This must be what feeling drunk is like!

Derek shifts where he’s sitting before answering. “Grade nine. Sort of.” He touches a single finger to her kneecap, pressing against the skin there. “You?”

It takes Casey a minute to locate her voice again, staring at his finger on her knee. “I was thirteen. It was a total pain.”

Derek moves his hand from her knee and taps her on the nose instead, like the jerk that he is.

—

“You know, you get to make up another rule for me,” Derek says.

Casey blinks. What had they been talking about? “I do?”

“Yeah. ‘Cause I… just said your name all not-official. Case - _Casey_. Ms. McDonald. Why don’t I ever call you that?”

“Ms. McDonald?”

He nods.

“Because you want to live to be eighteen one day,” she says. Oh snap! That’s right, she can still bring it.

Derek thinks about that for a moment, and then starts to crack up. “Ms. McDonald if you’re _naaasty_ ,” he drawls, and falls sideways against the windshield, laughing.

“Shut up, Derek,” she says, and leans sideways to rest her head against the window as well. The glass feels cool against her overheated cheek.

“Drink up, Casey,” Derek says. “You just called me Derek.”

“Uuuuugh,” she says, and hoists herself up again to grab the can next to her hip and take a swig. She falls back with relief, snuggling her face against the amazingly cool window, probably smearing her face oil or whatever all over the Prince. Like she cares. It feels _amazing_. It feels like ice cream on a hot summer day.

Derek wiggles his shoulders down a couple inches closer to her, so they’re facing each other.

“You’re terrible at this.”

“Bite me,” she says, and scratches the side of her cheek conspicuously with a single middle finger.

Derek snort-laughs at that, and Casey can feel his breath on her face. “Nice.”

The windshield wiper is digging into her shoulder, so Casey moves herself forward an inch or two, into a more comfortable position. Derek’s face is even closer to her now, his ridiculous chipmunk poof of a hairstyle falling across his forehead, his own cheek pressed up against the same glass as her own.

“We’re both terrible at this,” she agrees in a whisper. “We keep forgetting to make new rules now.”

“Yeah,” Derek agrees, just as softly.

They keep staring at each other, silently, and it’s starting to slowly, stupidly occur to Casey that what they’re doing isn’t normal. She and Derek don’t just… look intensely at each other without talking. This is _weird_.

She shifts over onto her back, gazing up at the ceiling of the garage again. It’s uncomfortable; she can feel the windshield wipers wedged awkwardly underneath her again. She bends her knees up to rest her feet flat on the hood, which helps.

“You know, if we were outside, we’d be looking at the stars,” she says, looking up.

Derek flips onto his back to stare up at the slatted two-by-four rafters of the garage with her.

“We could back the car out of the garage, get a sky view,” he suggests. “George and Nora might be asleep by now, they might not hear.”

She thinks about it, looking up through the branches of the big tree by the driveway at the night sky. She can almost imagine the chill of the night air outside the garage, how it would suck the warmth out of the metal underneath her. Derek’s shoulder would feel even warmer than it does now, pressed up against her own. Casey shivers.

She rolls over to her side to face Derek again, tucking a hand underneath her cheek. “Nah,” she says. “Let’s stay here.”

The fizziness between them fades again as they fall silent, replaced by that massive, thrumming feeling that keeps sneaking up on them. They’re lying facing each other, stretched out on the hood of the car. Casey draws a breath to put space back between them yet again, to crack a joke and break the tension one more -

Derek leans forward and presses his lips against hers.

… _What_.

She barely registers it as a kiss before it’s over. Derek’s face goes blank as he pulls away, blanching pale with something like shock or fear.

Oh _god_.

Derek kissed her. He _kissed_ her. How drunk is she? How drunk is _Derek_? He’s been drinking more than her, but then, he’s also got a lot more tolerance than her.

Casey reaches up to numbly drag a finger over her lower lip. Are they drunk? Is this a drunk kissing thing??

Casey realizes then that she’s still touching her mouth, and, worse than that, Derek is _watching her do it_. He’s breathing faster now, a flush on his cheeks that looks like dizziness or nausea. 

She lowers her hand.

“You kissed me,” she says finally.

She realizes, distantly, that her breathing is almost as heavy as Derek’s.

“I…” Derek begins.

“We had a _rule_ ,” she continues, over top of him. “A rule! You couldn’t kiss me and I couldn’t kiss you.”

Derek swallows, and she watches the motion of his throat.

“Why did you do it?”

“I didn’t…” he starts to say, winding up like it’s the beginning of one of their really good arguments, and she thinks, in a sudden wave of gut-wrenching panic, that she might not want to hear what Derek’s about to say next. Because if both of them talk about whatever this is… that’ll make it _real_. It’ll make everything a million times more uncomfortable and awful than it already is. Casey doesn’t think she can deal with that.

And she thinks, _I have a way to shut him up_. It’s a free pass, after all: Derek did this to her first, right? She has a get out of jail free card.

Casey leans forward and presses her mouth up against Derek’s, mid-rant, and he cuts off with a suddenness that should be hilarious (because she _shut him up_ , she gets the last word, she wins), but it’s… not.

Derek’s not breathing, which she can tell because her mouth is smashed up against his. They’re both frozen in place. It’s… kind of weird? Neither of them are moving, and both of their mouths are closed. It reminds Casey, in a moment tinged uncomfortably with hysteria, of that time she’d had to do CPR with a plastic dummy when her mom had made her take that first aid class in grade nine, when -

Casey’s head slides against the windshield, and Derek is kissing her back _hard_.

It’s teeth and dry lips and the taste of old chapstick and sour beer, and Casey would normally hate being kissed like this, except - she doesn’t. Not at all. She is _into it_ , it’s crazy how much she is into it. Derek slips his tongue into her mouth and just like that, they’re french kissing, and Casey’s head is swimming, she is drowning in a haze of how freaking great this feels.

(She knows that Derek doesn’t normally kiss like this, half-teeth and no finesse - she’s seen him with girls, she’s seen his dumb PG-rated soft lips routine fading into annoyingly persistent kisses that make her roll her eyes with how transparent teenage boys are.)

Casey bites Derek’s bottom lip and he moans, low in his throat, like he’s trying to stay quiet but he can’t. There’s something kind of… _sexual_ about the noise. A knot of horrifying, exhilarating, this-shouldn’t-be-happening nerves begins to churn low in her stomach.

And Casey can tell, dimly, that a part of her is _freaking out_ right now (they are definitely making out! This is not supposed to happen!). But that voice is buried hotly inside her, sharpening everything with a crazy urgency, _you know this is wrong_ a drumbeat in her head.

Then Derek tears his face away from hers, and just as suddenly as before: they’re not kissing anymore.

They’re both breathing hard. He’s only a couple inches away from her; his face a blurry, cross-eyed mass hovering in front of her. She focuses her gaze, and notices one of her hairs is stuck to the corner of his mouth, connecting the two of them like a strange, droopy thread of a spiderweb.

Casey sweeps her hair back over her shoulder, and watches with horrified fascination as the hair pulls away from the wet of Derek’s lip, dragging across his mouth.

“What are you doing?” he asks, sort of accusingly, like _he’s_ the one who’s somehow confused, and oh, no. No way. He is NOT going to put the blame for this on her.

“I don’t know, you started it!” she snaps.

Talking is so going to get them _nowhere_.

Casey launches herself at Derek’s mouth again. Derek reaches for her, then hesitates, his hand hovering by the side of her head like he’s not sure if he’s allowed to touch her even with his tongue buried completely in her mouth, before grabbing the back of her neck to drag her closer. His hand is heavy against the side of her neck, trapping her between the cool glass of windshield of the Prince and warm, damp skin of his palm.

Derek pulls away again abruptly, his fingers still wrapped around the back of her neck.

“I _know_ I started it,” he continues. “But you’re…”

“Oh my god, just shut up,” she says, and grabs his obnoxiously large belt buckle and yanks it toward her. The hood of the car is slippery enough that Derek’s hips slide a couple inches, and she slips a little bit closer to him at the same time, her body lacking the leverage to pull Derek’s greater weight completely on its own, even with the element of surprise. The metal of Derek’s buckle is cool against her overheated palm.

“Yeah, okay,” he says fast, under his breath, and kisses her again.

—

They make out for a while, and Casey wants to die of how hot this is. She doesn’t really understand how what they’re doing is so incredibly hot, because they’re just _kissing_ , normal french kissing like she’s done a dozen times before, hands in one place over clothing, but - the alcohol spins her brain, and she can’t stop thinking _Derek, this is Derek, oh god_.

And it’s not even comfortable - they’re at a weird angle, with their shoulders propped up on the windshield of the Prince and her elbow digging into hood of the car. She already feels like she’s going to have a sore neck tomorrow from the awkward position, like whiplash or something.

She thinks, _I can never tell Derek how hot this is, I will never hear the end of it_ , and a wave of mortification washes over her, just imagining his dumb, smug reaction.

Derek starts to push her backward, his knee nudging against her shins. She ends up with the windshield wiper biting into her back and an angle in her neck like she’s a slinky wound up too tight.

“Hey,” she gasps, when they both come up for air for a second. “Do you want to…” Her imagination runs out as the words leave her mouth, because _does he want to_ … what? All she knows is her neck is killing her and she wants to keep kissing Derek as long as she can get away with it.

Derek looks down at her, eyes dark and halfway between dazed and unnervingly focused, and she wonders with a sudden, electric jolt just what Derek thinks she’s about to ask him.

…What _is_ she asking him? Think, Casey, think!

“Want to, um,” She falters again, then in a flash of inspiration, nods behind them. “Maybe… uh, in the Prince?”

Derek licks his lips, which are redder than normal, bright and bruised-looking. It makes him look somehow both younger and strangely older at the same time.

“Sure.”

“Okay,” Casey says, and slides off the hood of the car on her butt like she’s on the slide at the playground.

She can feel that she’s drunk for the first time, really _feel_ it, when her feet hit the concrete floor. The whole world undulates alarmingly underneath her. She walks back trailing hand along the side of the car and slides into the backseat of the Prince.

They shut both of the back car doors at the same time, and end up staring at each other across the vast distance of the middle seat. Derek hunches awkwardly over his lap.

It’s even quieter in the car, the vehicle muffling the low, ambient noise of the neighborhood, and Casey is starting to think that her genius idea was actually a really terrible one. Whatever craziness that got them to kiss earlier seems to have dissipated along with the change of location; the distance between them seems insurmountable. There’s already a voice growing louder in Casey’s head, a refrain of _you were making out with DEREK?_ and _oh god, you were making out with DEREK, you idiot!_

Casey spends a couple quality seconds staring at her knees, trying not to think about the fact that she’s now somebody who knows what it’s like to french her stepbrother.

“So this is weird,” Derek says finally.

Casey laughs hollowly, and puts her face in her hands.

She sees him shift in his seat out of the corner of her eye.

“Hey, give me your hand,” Derek says.

“What? Why?”

She hears him sigh. “Just do it, okay, Case?”

She doesn’t call him out for the nickname (she feels like they passed that part of the drinking game, oh, a super long time ago). She holds her right hand out toward him, across the middle seat.

He takes her hand and turns it, so her palm is up.

Then he kisses it, and it’s kind of obscene what his tongue feels like against the sensitive skin of her palm. Casey’s pretty sure that if she’d been standing, her knees would have buckled, because _holy shit_.

Oh god, she must be so drunk. Derek is _kissing her hand_ , and it’s incredibly hot, in this weird way? She doesn’t understand this at all.

“Give me your other hand,” he says. His voice is lower now, sort of hoarse. Casey starts to breath faster again.

She has to turn to face him to hold out her left hand, and she pulls her leg up on the seat, tucking her ankle underneath the opposite thigh.

Derek kisses her other hand, and Casey shivers and moves her left palm to his cheek. The air feels thick and hot around them, and the next thing she knows they’re kissing again.

It takes them a minute to figure out how to fit into the backseat; Casey ends up with her knees bent up on the seat, and Derek has one foot on the floor of the car, his other knee between her legs. His hips are sort of angled away from her, and it eventually occurs to Casey it’s probably because he’s got an erection and he’s trying not to press it up against her. The thought makes her dizzy.

And maybe it’s because they both know they choose to continue doing this (instead of accidentally ending up kissing, the way it’s totally possible to accidentally end up doing!), or maybe because they’re in the backseat of the Prince, but it feels different this time. It feels _dangerous_. Like things could go further, if she lets them. People have SEX in the backseats of cars.

The vague feeling of wrongness that had settled in her stomach earlier twists, turning hot and urgent, Derek’s tongue in her mouth, and she can’t stop thinking about the fact that Derek almost certainly has to have a boner right now, and Casey wants _more_. She can’t figure out how to get her body to tell Derek what she wants. Her mind is heavy with the late hour and alcohol and the way everything has been so strange between them.

Derek’s left hand starts to creep up her side.

She’s caught between wanting to snicker (because of course Derek’s trying to touch her breasts, what a shocker) and squirming down lower, into his hands. Her nipples are hard and so sensitive already, rubbing in her bra up against Derek’s chest. She remembers how achy and awful and tight her nipples felt when she wore his jersey without a bra, the fabric constantly scratching her, and somehow that all jumbles up hazily in her head and comes out as she really wants Derek to touch her boobs, like, _right now_.

His slowly moving hand makes it just underneath her left breast, then traces a circle up around her boob, over the top of her t-shirt.

The fact that he’s barely even touching the side of her breast makes her squirm even more, heat pulsing between her legs. She wonders what he’s waiting for. She’s been to second base before, and it was awesome, and god, why isn’t he just _doing it_ already?

She arches her chest out, hoping he’ll get the hint, but Derek’s hand remains resolutely in the side-boob area. He’s stroking her side now, just under her armpit, running a finger up and down her ribs, like that’s somehow a normal thing to do.

“You can touch my breast,” Casey says finally, annoyed at being forced to say the words.

Derek huffs out a choked laugh, and Casey winds up to snap back at him (like he’s one to talk!), but then his thumb brushes against the front of her shirt, over her nipple, and she slams her mouth shut. She feels Derek’s hand hesitate, then do the same motion again.

“You’re so hot,” Derek says, low and almost under his breath. Like he’s not even talking to her.

She shifts a bit. “I thought I was gross. Grosszilla.”

“I mean, that too,” Derek says in something a bit closer to his normal tone, but his eyes are dilated black and and he’s staring at his hand on her breast. It’s so indecent that he’s _watching_ himself touch her, Jesus. She wonders just how drunk he is.

“Can’t take it back,” she says, trying to sound flippant, but like all she can feel is his fingers brushing against her nipple again. “You think I’m hot.”

Derek shifts his weight off his right elbow and rolls his hips closer to hers to keep from slipping sideways off the car seat. Casey shoves her hands underneath Derek’s t-shirt, on the naked skin of his back, rucking up the fabric.

“Say it,” she goads. “Say it again.”

“No way.”

“C’mon, do it.”

Derek kisses her again instead.

They kiss until Casey is writhing, her hand shoved up underneath Derek’s t-shirt, trying to rub her thighs together. She’s so into this, and she knows that if she can pull Derek further on top of her it’ll be even better. She grabs his side and tries to wrestle him closer to her.

His hips turn into her, and she can feel Derek’s erection up against the front of her thigh for the first time, and oh fuck, oh fuck, oh fuck oh _fuck_.

“Oh my god,” Derek pants, and his hips buck against hers, pressing down into her like he’s not even sure what he’s doing.

He kisses her again, different than before, sort of wetter and sloppier, and she arches her hips back up against his this time. And that’s it, they start dry humping, pressing their hips together with Derek’s boner wedged between them.

She’s done this before too, with Max, and thought it was hot but also kind of stupid at the same time. It’s just wiggling your hips against a guy, right, even though Max has seemed to like it a lot. But Derek’s hands are palming her breasts, and her nipples feel so tight and the friction of the fabric of her bra against them feel unbelievably good, and oh god, Casey is _so turned on_ by all of this. Derek shifts, settling more of his weight on top of her, and she can feel the bulge of Derek’s dick against the inseam of her jeans now, rubbing up really close to the inside of her crotch sometimes. It feels so immediate and so freaking _there_ even with two layers of clothing trapped between them.

And she can’t get over the fact that she’s doing this with _Derek_. Derek, her sort-of-brother, who she fights with constantly and brushes her teeth next to and occasionally has everybody-learns-a-moral moments at the dinner table with. Casey’s stomach scrambles itself like a sexually confused omelet. God, this is so _wrong_ , she shouldn’t be doing this, what are they doing??

Derek looks like he’s basically out of his mind, his mouth going slack when he’s not kissing her, his pupils dark and fat. They’re grinding on each other, and it’s so stupidly hot Casey can’t deal with it. It’s awkward too, because her knees are bent up to fit on the backseat and Derek is sort of cramped into the space on top of her, one leg still off the bench to keep himself from rolling off, but somehow how constricted and uncomfortable they are just makes it more real.

Casey’s just starting to get that good, aching feeling building up inside of her, sweet and itchy and unfulfilled, when Derek’s breathing hitches and his hips stutter and then he buries his face in her neck.

Because Derek just…

Derek just…

Oh _god_.

“Fuck,” Derek groans, and she feels the word against the skin just underneath her jaw. “This is so embarrassing.”

“Oh my god,” she says, trying not to freak out.

Adrenaline pumps through her system and she feels keen, on edge, all these turned-on feelings still bouncing around inside of her. She wants _so much_ , she wants it like an ache, and she can’t anymore, not with Derek lying limp and heavy on top of her.

Casey slowly unwraps her arms from around Derek’s back.

Derek sits up then. He readjusts himself in his jeans, not looking at her. She flushes hot to see a little wet spot, darker than the rest of his pants, by his crotch.

Casey pushes herself up to seated next to him. Her head spins drunkenly, unpleasantly with the change in altitude.

Derek’s still not looking at her.

“I don’t…” Derek starts to say, speaking somewhere over the top of her head, then tries again. “That was, um. Really… hot,” he says finally. She can hear the space where he’d been about to say another word. She wonders what that might have been.

“Right,” Casey agrees faintly.

“I have to…” Derek gestures at his pants, then to the door of the garage, where their whole normal, regular, nothing-ever-changes life waits for them. “You know.”

Casey swallows.

“Right.”

Derek grabs the bottle of vodka and the juice glasses off George’s workbench, and Casey is able to think clearly enough to shut the trunk of the car, where they’d been tossing their empties. Derek looks super uncomfortable as he waits for her, hunched over at the waist. She thinks, with no small amount of hysteria, that it looks like he just peed himself, a little bit.

She thinks about telling Derek that, turning it into a dumb joke at his expense, but then she remembers what Derek _had_ been doing that resulted in a wet spot on his jeans, and the words get stuck in her throat.

Casey follows Derek back into the dark kitchen. Derek puts the vodka away while she rinses the glasses, trying to put the shot glass away exactly how she’d found it.

The part ways in the hallway outside their bedrooms in silence, and when Casey sleeps that night, she dreams unsettling things she can’t quite remember in the morning.


	6. Post-Game

**Notes for the Chapter:**

> Thank you to my beta readers for this chapter, ghostcat and htbthomas!

She wakes up with a pulsing headache, a sour, twisted feeling in her stomach, and a hickey on the left side of her neck.

Casey stares at her neck in the bathroom mirror for a while, some dim, screaming part of her brain insisting that this is very, very, very bad, but then the sickness in her stomach kicks in and she decides to throw up in the toilet instead.

She stumbles into the shower after that, turning the hot water off when she starts to go light-headed in the steam, and shivers her way through getting clean. She pulls on a pair of yoga pants, a tank, and an off-the-shoulder top she wears for dancing sometimes before stumbling downstairs, not sure what her stomach might be able to handle but feeling like she needs to try to eat or drink _something_.

At least she doesn’t have to go to school today. Thank god. She takes back everything she vaguely remembers thinking last night about drinking being cool or exciting or interesting, because she NEVER wants to feel this way on purpose again. This is the _worst_. Why do people do this to themselves? Is everybody else really that dumb??

Her mom is cooking bacon in the kitchen, singing cheerfully along with the radio, and the combination of the thick, smoky, grease-smell of the bacon, the light streaming in through the windows over the sink, and the idea of somebody being happy when Casey feels like _this_ makes her want to stab herself in the brain. Ugh.

“Morning,” Nora says, smiling at her and holding a spatula. “Want some bacon? I’m making eggs in a couple minutes too.”

“No, thank you,” Casey mutters, and slips down to sit on one of the kitchen island stools, exhausted from the long, arduous, terrible journey of walking down a whole entire flight of stairs.

Her mom frowns over at her. “You feeling okay, sweetheart?”

Casey summons up the emotional and physical energy to manage a shrug, and then thunks her forehead down on the kitchen island.

Nora smooths a lock of hair back behind Casey’s ear. “What’s wrong?”

She _cannot_ say that she has a hangover. _Don’t say you have a hangover, don’t say you have a…_. “My stomach is upset. And I just don’t feel well.”

“You poor thing,” Nora says, and Casey feels such a well of gratitude at the words she almost wants to cry. “Do you want me to make you some toast?”

Casey nods, nose smooshed up against the table.

Her mom fusses with the toaster while Casey greedily soaks in the coolness of the kitchen island counter through her forehead. “Derek wasn’t feeling that great earlier either,” Nora says, flipping the bacon one more time. “I wonder if there’s a stomach bug going around.”

Derek.

 _Derek_!

Casey’s head pops up, then she winces at the sudden motion. “Is he up?” she asks, looking around with her head in her hands, like maybe Derek’s been sitting next to her this whole time like a creeper and she just never noticed.

“Not anymore. He went back to bed a while ago.”

“Oh,” Casey says, and stares down at the un-buttered toast and glass of water that Nora sets in front of her instead.

She munches her way through the toast and takes sips of the water. It seems to help. Edwin and Lizzie and Marti invade the kitchen once the smell of bacon works its way up to the second floor, and Casey excuses herself and runs away from their screaming and fighting and general loudness and activity and awfulness.

She stares at the closed door to Derek’s room in the hallway upstairs, then walks past to her own room. She falls asleep again within minutes.

—

Through careful planning, a bit of dumb luck, a strategic skipping of dinner, and a dual hangover keeping both Derek and herself out of commission for the day anyway, Casey manages to make it to school on Monday without having to talk to Derek after… _after_.

It’s the little victories, really.

While Mrs. Wilson drones on about the rebellions of 1837 in first period, Casey tries not to think about making out with Derek. She’d been out of it most of the day yesterday, alternating between trying to avoid Derek and feeling dreadfully, sickly hungover, so this is basically the first time she’s really sat still and had to _think_ about what had happened on Saturday.

It was… it had been… ugh.

It can’t have been that good! She’s kissed guys who were much cuter than Derek. Guys she’d actually _liked_. Her self-respect demands that making out with Derek has to rank low on that list. It just has to.

Maybe it’s the alcohol. People talk about beer goggles, right? Maybe that’s what the term means, that you can make out with your super annoying stepbrother and for some reason it ends up being the most intense thing you’ve ever done in your life, but that’s a-okay, because it’s just the alcohol talking.

Casey breathes a sigh of relief. It makes sense, really. _Beer goggles_. Sure, she might have been wondering what it would be like to kiss Derek beforehand, there might have been this weirdness building up between them, but that doesn’t have to _mean_ anything.

Her memories of Saturday night are strangely fragmented anyway, like slippery flashes of a dream. If it had really been that great, wouldn’t she remember more of it? Because when she thinks about kissing Derek, all she remembers is a vague sensation of teeth and Derek’s lips against her neck. The sensation of liquid and heat, heavy inside of her. The weight of his body, cramped and awkward in the backseat of the Prince. They way they’d both been _panting_. The desperation, the feeling like she was trying to claw her way out of her own skin, like all the things she’d felt were too big for her to contain, like she was going to -

“Ms. McDonald?”

She jumps in her seat, fumbling her pen.

Mrs. Wilson is facing the class. “Could you read the section in the textbook on the Act of Union out loud for the class? Starting at page 122, please.”

Casey clears her throat, face hot, and flips her textbook open.

—

Casey makes it to lunch, cranky and restless with the fact that she hasn’t been able to stop thinking about making out with stupid, dumb, awful Derek Venturi all morning, before her luck turns.

“Casey!” Derek yells across the hallway, and Casey closes her eyes, a hand on her locker. Of course.

“Hey, Derek!” Emily says, smiling. “What’s up?”

“Mind if I grab Casey? Got to discuss something with the step-sis.” Derek swings his arm around Casey’s shoulder and grins at Emily, then digs his knuckles into Casey’s scalp, messing up her pigtails.

Casey shoves him off, scowling and straightening her hair. “Don’t touch me, Derek.”

Derek’s eyebrows goes up, and Casey thinks he’s about to say… something… until Emily laughs. “Glad to see the two of you are back to normal.”

Casey slams her locker shut. “Right.”

“Seriously, though. You have a minute, Case?” Derek asks.

Casey shifts her glance at Emily, then back at Derek. She’s not sure if she should. The avoidance thing really seems like the way to go here.

“Why?”

“Venturi family business,” Derek says. “You know.”

“Don’t you mean _McDonald_ family business?”

“E-I-E-I-O,” Derek sings, then moos.

Emily laughs, and Casey slams her locker shut. “Fine,” she says. “You have,” she looks at her watch, “five minutes until the next class starts, so talk fast.”

“Hey, I’ll see you later, Casey, okay?” Emily says. Casey watches Emily walk away down the hall before facing Derek again.

Casey gestures. “So, talk.”

“Not here,” Derek says, motioning as if to grab her arm, but drops his hand instead. “Come on.”

Derek leads her through the school to the gym, which is empty and silent with everybody at lunch. He doesn’t say anything while they’re walking, which suits Casey just fine. Hopefully they can make it through the next five - she looks at her watch again, _four_ \- minutes without actually interacting at all. That would be pretty sweet, actually.

She sneaks a glance over at him when they’re halfway across the gym floor, the squeak of their sneakers loud in the cavernous room. She hasn’t just... _looked_ at him since Saturday, really. His hair is its normal hockey cut, ear length and half-wild. He’s wearing a brown t-shirt underneath his black leather jacket. And under the collar of the jacket, at the base of his neck, is a faint purple-black bruise. Casey stares at it for a moment before realizing she’s staring at a hickey.

Derek has a hickey.

Derek has a _hickey_.

She’s suddenly, scaldingly aware of the matching bruise just above her own collarbone, covered up by the high-necked shirt she’d picked out that morning. Her heart starts to beat faster.

She gave Derek a hickey she doesn’t remember. Her! Drunk Casey, the Casey-from-Saturday-night who had made out with her stepbrother in a half-remembered haze of hormones - she’d _done_ that to him.

Derek’s lips are pressed together. He hasn’t looked at her or said anything since he’d given her that stupid noogie in the hallway. Despite Casey’s earlier feeling that she’d be happy if they never talked again, it’s starting to weird her out now. Derek talks shit; that’s what he does. He gets out of situations with a smirk and a complete lack of self-decorum, a too-charming grin and an unfettered belief in a world that revolves around him.

They round the corner behind the stacked-up bleachers, a small corner of privacy in a school overrun with people. Derek turns toward her, half-frowning.

Casey kisses him.

She’s not really sure why she does it. She doesn’t think it about it.

She just - _does_ it.

She crashes into Derek awkwardly, knocking him a step backwards, a startled _oomph_ escaping his lips. She shoves her hands up into his hair and pulls his face down to hers. Derek’s back hits the painted concrete blocks of the gym walls. Derek’s taller than her, a fact she knew but hadn’t really understood until she realizes she had to stand on her toes a bit to get to his mouth.

Casey pushes her body closer to his, propelling them both backwards so that Derek’s shoulders hit the concrete behind him. They keep kissing.

Their teeth bump. Derek’s hands are in her hair, his fingers wrapped up in her low pigtails, and when he shifts his hands, he pulls strands of her hair out. It stings.

And she forgets that they’re making out at school (where anybody could see them!) and she forgets how much she hates Derek (he’s the worst!). She forgets how she was pretty sure they should never talk to each other again (nope, definitely not!). She forgets all the reasons they never should have started whatever-this-is in the first place (their parents are married; oh god, they’re supposed to be _siblings_ ).

Derek’s hands are her waist and he’s half-slouched, kissing her back, his tongue in her mouth. He squirms a bit against the wall, and she can feel the bulge of his dick against her hip already. The idea of Derek with a hard-on, in the middle of school, is crazily out of place. It’s _wrong_ in this way that somehow makes everything strangely hotter. Because: she can _do_ this to him, just by french kissing him a little. She can embarrass Derek like this, she can make him want her so much that if anybody caught them, he wouldn’t even be able to hide it. It almost makes her want to laugh.

The bell rings.

The sound is like a bucket of cold water to Casey’s face.

Casey pulls herself away from Derek, breathing hard. Something like shame starts to churn in her stomach. What was… what…

Casey backs away one step from Derek, then two. Then she turns and runs.

—

She misses the first ten minutes of her next class hiding in the girl’s bathroom, sitting on the toilet, staring at the flimsy metal door.

Why had she done that? She can’t think of a single excuse - they hadn’t been drunk this time, they hadn’t been arguing, they hadn’t been _anything_. She’d just… attacked Derek’s mouth, in the school gym, where anybody could have seen them.

She can’t even blame Derek. It had been _her_ , sexually assaulting her own stepbrother, in the broad light of day.

She groans, and drops her face in her hands.

She sits in the silence of the empty, echoing bathroom for a couple more minutes before flushing the toilet, splashing cold water on her face, and walking out to take a tardy in her next class. She almost skips the afternoon class she shares with Derek, but finally, in a rush of sheer determination and gut-wrenching panic because _Casey McDonald doesn’t skip classes_ , makes herself walk through the classroom door, only to discover Derek skipped instead.

She’s never been so happy that Derek’s basically a juvenile delinquent.

—

The rest of the day goes by in a blur. Casey stays late at school, doing homework, and rushes home just before dinner, slipping into her normal seat across from Derek right as the food starts getting passed around.

She doesn’t look at Derek, sitting across from her. She’s never going to look at Derek again. Yup, that’s what she’s going to do. Never again!

“Casey, sweetie?” her mom says, and waves a hand in front of Casey’s face.

Casey blinks.

“What?”

“Could you please pass the salt?” George asks from the other end of the table, like he’s repeating himself.

“Oh, right!” She grabs the shaker and shoves it at Lizzie, in George’s direction. “Salt. Right. Here you go.”

“Thanks,” George says, something amused in his voice.

“And what did you do today, Edwin?” Nora asks.

Edwin goes off on a long, strangely political diatribe about the machinations of his class at school, while next to him, Marti stares at the green beans on her plate like she’s trying to make them disappear solely through the power of thought. Lizzie taps her feet, _tap tap tap_ on the floor. George eats three of the dinner rolls, one after the other, and Nora purses her lips together and nods thoughtfully at every third sentence or so that Edwin says.

Casey sneaks a glance across the table at Derek.

Derek’s staring at her.

Casey snaps her gaze away.

She volunteers to help with clean up after dinner, clearing the table and trying to give Derek as much time as possible to vacate the immediate area. Lizzie empties the dishwasher and Casey rinses the dishes, filling the machine again.

She can see Derek’s head on the couch in the living room, hanging around. Ugh. Why is he still here?

Derek’s watching something on the TV, seemingly engrossed, when she finally finishes the dishes. Maybe he won’t notice her sneak upstairs. She wipes her hands dry, takes a deep breath, and starts to edge her way towards the stairway. The back of Derek’s head stays facing forward. Success! She tiptoes her way up the stairs, and makes it to the top and a glimpse of her bedroom door when a hand closes around her elbow.

“Hey, Case,” Derek says, and pulls on her arm.

“ _Derek_ ,” she hisses, and tries to wrench her arm away. “Let go! What are you doing?”

“What are _you_ doing?” he repeats back - nonsensically, as far as Casey is concerned.

“I asked you first!”

“I - just - c’mere, for a sec, okay?” He tightens his grip, and pulls them down the hallway to the door of the games closet.

She catches a glimpse of shelves of half-broken plastic toys and the spines of once-loved picture books stacked high above their heads as he pushes her inside the closet ahead of him. A single bare, unlit bulb hangs above them, the chain swinging like a guillotine. Derek doesn’t yank the light on; instead, he shuts the door behind them, plunging the room into a dim darkness, only a thin sliver of light showing around the frame of the door.

“Derek,” she whispers, “seriously, what are you -” 

Derek makes this odd, urgent sort of sound, and kisses her in the darkness, hard.

She stumbles backwards from the force of the attack on her mouth, and kisses back instinctively for one blind moment. Derek grabs her hips.

She pulls away.

“Derek! What are you doing? You know - I mean… we can’t -” 

“Somebody’s going to hear you if you keep talking,” Derek says, his voice disembodied, and the vague, blobby Derek-shaped form leans in and starts going to town on her mouth again.

Her protests die in her throat. Derek mutters something she can’t quite understand under his breath, and slants his mouth more fully against hers. Casey takes a second step backwards, and her back hits one of the shelves that line the games closet. Some sort of cardboard box - a game or a puzzle which is, statistically speaking, almost certainly missing some of its pieces - digs into her shoulder blades.

Derek crowds up into her space, and since Casey can’t back up anymore, they end up pressed together from their shoulders to their toes. Derek’s body is _overwhelming_ this close. His hands are all over her body, and Casey has never seen Derek like this: sort of half-crazed, like he’s going to die or something if he’s not kissing her.

And Derek smells _good_ pressed up this close against her, the clean smell of soap and boy shampoo overwhelming in the small, claustrophobic space. Casey makes this embarrassing noise, a sort of overwhelmed squeak. Derek’s fingers tighten almost painfully on her waist.

“You’re driving me crazy, Case,” Derek mumbles against her mouth.

Oh, it is so like Derek to blame this on HER.

She opens off her mouth to tell him off, to say - something, she’s definitely going to say _something_ , when they hear somebody coming down the hallway, toward the closet.

“Why don’t you get it yourself, Edwin! Why do you always have to -“

Derek jumps back, and manages to find the chain for the light bulb right as the door yanks open. Casey freezes. Lizzie stares at the two of them, apparently just… hanging out in the games closet. For some reason?

“Oh, hey, Casey! And… Derek? What are you guys doing here?”

Casey turns to stare at the wall of board games, fussing over the column of faded titles. Derek plucks a copy of Mousetrap from the bottom shelf and holds it up like it’s the answer to all his dreams.

“Just looking for this,” he says, and brandishes the box in Lizzie’s direction. “Obviously.”

“You know we couldn’t find half the pieces to that game the last time we tried to play it,” Lizzie says, and pulls a copy of Sorry off the shelf.

“We’re going to fix it,” Casey blurts out. “Fix the… game. I mean, the missing pieces - we’re going to figure out what to do without them. Because - that’s a thing?”

“For a school project,” Derek adds.

“The two of you are doing a school assignment together?” Lizzie asks, frowning.

“Nope!” Casey says, and snatches a copy of Battleship from behind a stack of puzzles. “Different games.”

Lizzie frowns. “High school is weird.”

Derek pats Lizzie on the head. “You’ll learn about it when you’re older.”

“Okay,” Lizzie agrees doubtfully, and heads back downstairs with the battered copy of Sorry.

Casey looks at Derek, and Derek looks back at Casey, and they both bolt at the same time, heading for their rooms with their respective board games.


	7. Overtime

Derek knocks on her door two days later.

“Derek,” she says formally, and swivels her desk chair around to face him. They hadn’t made out at _all_ yesterday, no matter how much she’d wanted to (and she’d _wanted to_ , which Casey really doesn’t know how to deal with right now). But despite everything they hadn’t made out since Monday in the game closet, which Casey thinks is a moral victory deserving of the highest sort of praise. Go them!

They’re really getting the hang of this whole not-making-out thing. They are _so_ good at this.

“Hey, Case.”

“I was actually hoping we could talk,” she says, inclining her head. They’re going to be so grown-up and practical about this. It’s going to be great! “Come in.” She gestures grandly at her room.

Derek sits down on the corner of her bed closest to her, his knees almost bumping hers.

“Talking is overrated,” he says, going off script right away. “What if we - and bear with me, I know it’s a crazy idea - what if we just _not talk_ , instead.”

Casey frowns. Um. “What if we _don’t talk_?” What a dumb suggestion!

“Yeah.” Derek says the word like it’s the easiest thing in the world, like, duh. Why was she expecting anything else? This is Derek, after all.

“Well, it seems like that plan hasn’t been working very well for us so far.”

“I disagree. I think it’s working great.”

“You would,” she mutters.

“I do.”

“Don’t you think that instead of -“ Casey can feel heat seeping into her face, turning her cheeks the blotchy red she hates. “Uh… that maybe we should… stop?”

“Stop?”

“Yeah. Stop.” She waves a hand around, encompassing everything around them: the house they live in, the siblings they share. Their parents, who she’s pretty sure didn’t marry so their teenage son and daughter could hook up whenever they felt like it. “Because.”

Derek flops backwards on her bed and seems to think it over, frowning at her ceiling.

“Nah,” he says finally. Like it’s that easy.

“What? Just… no? You think we should just keep on…” She trails off again, then settles for flapping her hands around again in Derek’s direction. Surely he’s not suggesting they _keep_ sucking face, god.

Derek lifts himself up on his elbows. “Why not?”

“Where to start? One: our parents are definitely married. Like, _married_ married.”

“So we’re doing a _Clueless_ thing or whatever. We can do that.” She can hear a thin note of defiance in the words. like he’s looking to fight somebody about this.

Casey opens her mouth, then closes it again. “Well, we… we can’t tell anybody. That doesn’t bother you?”

“Why, does it bother you?”

She pretends nonchalance, an anti-Casey attitude that he’s got to know is at least somewhat fake. “A little,” she sniffs.

“Well, we don’t have to tell anybody right _now_ , do we?”

“Right at this second?”

“Sure. Right now. We run downstairs, call an emergency meeting with the fam, and tell everybody what’s been happening, right now.”

“I mean - I guess not.”

“Well, there you go. We don’t have to tell anybody today, or even tomorrow. But… that doesn’t mean we’re _never_ going to tell anybody, right?”

“Is this Derek-logic? I feel like this is Derek-logic.”

“Look, what I mean is - obviously you’re into me. And who could blame you?” Derek spends a moment looking super smug. Casey rolls her eyes. “And I’m - I mean, you’re - you’re not half-bad. Or whatever.”

“Wow.”

“I know.”

“Way to woo a girl, Derek.”

Derek sits up again, looking at her closely, and leans in to where she’s sitting at her desk, almost touching his nose with hers. “So you’re saying you want me to woo you?” he whispers, and Casey feels suddenly hot. He’s too close.

Casey pushes Derek away, shoving his shoulders, and he collapses backwards on her bed again, laughing.

“So,” he says, after he’s stopped laughing. “All I’m saying is we don’t have to tell anybody until we want to. Just not this instant, eh?”

“I guess,” she agrees, doubtfully. “I mean, I guess, for a while - for a little bit - it would be okay to not tell anybody. But -“ This conversation isn’t turning out the way that Casey had role played in her head. “We really _shouldn’t_.”

“But I think we should.”

“Why?”

Derek hesitates for the first time, and it occurs to Casey that this whole conversation they’re having - Derek hasn’t stuttered _once_ , despite his normal, dumb allergic reaction to all things that deal with actual human emotions. And sure, she guesses they’re not really talking about real, hardcore feelings or anything (since they’re mostly talking about whether or not they should continue to make out, which is definitely a subject in Derek’s wheelhouse), but Casey can hear for the first time how careful the things Derek is saying are.

How he’d probably thought about what he was going to say to her.

Casey’s heart starts to beat faster.

“Because I want to,” he says finally. He speaks slowly, like he’s trying out the words as he says them.

The pulse in Casey’s ears suddenly seems very loud.

“I can’t stop thinking about it,” he continues, staring at her. “And I’m not saying we have to do anything crazy, or whatever. We don’t have to tell anybody, we don’t have to do anything we don’t want to. It’s just that, for right now, I’d just like to - I don’t know. I’d like to -”

“Keep sticking your tongue down my throat?” Casey asks without thinking. As soon as the words leave her mouth, she wants to die of embarrassment. God! Making out randomly with Derek is totally warping her brain. Maybe he’s infecting her with his malcontent teenage awfulness.

Derek sneaks a glance over at her. “It sounds hot when you say it like that.” Weirdly, it doesn’t sound like he’s joking.

Casey clears her throat, more disconcerted by that than anything else he’s said so far.

Derek pulls himself a little closer to her again.

“What are you doing?” she asks, more than a little unnerved.

Derek licks his lips, and Casey feels her gaze flicker down to Derek’s mouth before she can stop herself. “Would it be cool if I kissed you again?” he asks.

Her heart stops for a moment, then restarts in a wave of panic. She shifts backwards a bit, desperately trying to keep a hold of herself and the whole situation. “Oh, so _now_ you’re asking?”

Derek grins at her, with more cheek than she’s strictly comfortable with. “You didn’t ask me when you jumped me in the gym on Monday.”

“You’re seriously going to bring that up!?”

“C’mon, Case, that was, like, the single hottest thing that’s ever happened to me at school.”

“Oh god.”

“By far.”

“I can’t believe I made out with you at _school_ ,” she moans.

“…By _ever_.”

“What would my teachers think? What would _Paul_ think?”

“I don’t know what type of information you normally share with your teachers, but you could probably not tell them that part.”

“It was just so - not me, you know?”

Derek smirks. “It _felt_ like you.”

“Eew, Derek, gross!” She swats at him, and Derek cracks up. Ugh, he’s such a _boy_.

“All I’m saying is,” he leans back in close to her, “you could do it again.”

“Could I?” she asks.

He hesitates, and some expression Casey can’t decipher flickers across his face. “I wouldn’t stop you.”

She feels herself drift closer to him, despite herself.

And there are so many reasons why this is a bad idea - Casey made a list yesterday in her notebook, handwritten, with several key points emphatically underlined, DO NOT MAKE OUT WITH DEREK AGAIN, FOR REAL THIS TIME - but she’s is surprised to discover that, deep inside of herself, she really just - _doesn’t care_.

She _likes_ Derek. She likes Derek! _Derek_! And sure, sometimes she also can’t stand Derek either, but maybe those feelings are just two sides of the same coin.

She really does want to kiss him again.

“You should be so lucky,” she whispers, and Derek exhales softly.

She’s not sure who kisses who this time, both of them shifting together, toward the same place.

It’s chaste, just the faintest touch of his lips against hers. It’s - _nice_.

…It’s the middle of the afternoon.

The sun is shining.

Actual birds are actually chirping outside of her actual window.

And she is kissing her stepbrother, on purpose, in her own bedroom, sitting on her bright blue rolling chair.

She’s suddenly aware of how very weird, how very _funny_ it is, this thing that they’re doing.

Derek pulls back a little to frown at her. “What’s with the laughing?”

Which just makes Casey laugh harder.

“You’re such a dork,” Derek says, and pokes a finger against her stomach.

“ _You’re_ the dork!” Casey retaliates, flicking him on his thigh.

“Dork? _Dork_?” Derek yanks her off the chair and tackles her back into the mattress then, and Casey is laughing, almost hysterically, the whole thing they’re doing suddenly hilarious.

“You’re dead, D,” she says, and tickles him, right below his ribs.

Derek convulses on top of her, laughing, his weight heavier than she’d expected, pressing her down. It’s harder to breathe with him on top of her.

Strangely, it helps. It’s helps a lot. She knows how to wrestle with Derek, she knows how to do _this_ , and it’s a lot less weird and overwhelming than everything else they’ve been doing.

“You are…“ Derek gasps, laughing, “… _so_ dead. I’m gonna get… you. You are… ”

“Oh really? You’re gonna get me? Is that right?”

Derek slides a hand up her side and twitches his fingers just under her armpit, and Casey kicks a leg convulsively, giggling and trying to bat Derek off. He’s working the weight advantage, leaning down hard into her to keep her from squirming away.

“Stop it!”

Derek doubles down. “No mercy!”

They fight each other, laughing and shoving, until they end up sprawled next to each other on top of Casey’s bed, breathing hard and buzzing with physical exertion. Derek grins up her ceiling. They’re not touching, but Casey is intensely aware of her hand on the mattress, only a couple inches away from Derek’s.

“You’re such a freak,” Casey says, and starts to laugh again.

“It takes one to know one.”

“Ha ha.”

Casey sits up and shakes out her messed-up hair, combing her fingers through the tangles, then pulls her hair back into a low ponytail. She glances over at Derek. He’s watching her, that strange expression back on his face.

“What?” Casey double-checks for any escaped bits of hair. “Is something wrong?”

“No.”

Casey rolls her eyes. “Okay, weirdo. C’mon, I’m starving.”

Derek jumps up, back into motion, back to normal in the blink of an eye. “You’re speaking my language, Case.”

“What, food?” Casey thumps her chest. “Me Derek, me so hungry.”

“Couldn’t have said it better myself.”

—

“And that’s when I say to the guy,” George gestures with his fork, flourishing it like a sword, “see if I care if you file that deadline extension!”

“Oh my,” Nora says, amused.

“What’d you do?” Marti asks, eyes wide, like she’s actually following George’s thrilling tale of office politics and lawyer in-fighting.

George puffs up another inch. “Well, I went to the guy’s boss, right, and I said…”

Casey can hardly listen to the conversation. She can’t stop thinking about why her and Derek had just talked about upstairs. About what she’s pretty sure the two of them just agreed to _do_ again.

Derek catches her eye across the dinner table and arches an eyebrow. It sends a crazy thrill down Casey’s spine.

She’s kissed Derek! Technically, she’s more-than-kissed Derek. They’ve, like, hardcore made out. Derek actually came in his pants after grinding on her leg for a while and sticking his tongue in her mouth. God, it seems so _dirty_ , thinking about the two of them doing that, when she’s sitting here, at their pleasant and brightly lit family dinner table, with their parents and siblings happily chatting around them.

They could make out again tonight. The realization floors her. She could slip over to Derek’s room after everybody else is in bed, or he could come over to her bedroom, and they could… they could…

Casey looks back down at her plate, heart beating fast.

Which is when Derek slides a foot up her calf, pressing up against the back of her leg, and Casey promptly chokes on a piece of potato.

“You okay, Casey?” her mom asks, interrupting George, as Lizzie helpfully pound her back. Derek’s laughing on the other side of the table, smirking to himself, the _jerk_. She can’t believe she’d just been thinking about kissing him again.

“I’m fine, I’m fine.” She waves Lizzie off and gulps down the rest of her glass of milk.

“You sure?”

Casey takes a deep breath in, eyes watering. “I’m sure.”

“Casey’s a klutz even when it comes to eating,” Derek explains cheerfully. But there’s a funny slant to the way he’s acting, catching her eye again, that makes her think that he wants her to play along with what he’s doing.

_We don’t have to tell anybody right now._

“You should talk, Derek,” she says, careful to make sure to sound just like normal, like they way they interact all the time.

“Hey, now.” George holds both hands up. “Keep it civil, you two.”

“I will if she will,” Derek says, stabbing a finger in her direction.

Casey puts on her Going To War face and glares. She glares hard. “I will civil you into the _ground_ , D.”

“Is… that a good thing?” Nora asks the table at large. George shrugs.

“I like ketchup!” Marti announces out of nowhere, and Derek leans over and fist bumps Marti behind Edwin’s chair.

“You go, Smarti.”

The conversation devolves from there into a spirited debate about whether or not ketchup counts as a vegetable. Casey waits a couple minutes before putting her plan into motion.

She stretches her foot out underneath the table, feeling blindly with her toes. She’s terrified that she’s going to run into the wrong person and end up playing footsie with Edwin or Lizzie or her mom, of all people. The whole thing would be ridiculously embarrassing. So Casey moves carefully, trying to judge everybody’s relative positions.

Her foot nudges another sock-clad foot, and, across the table, Derek stops chewing.

At the end of the table, George scoffs loudly. “Then why do tomatoes have seeds? Think about that!”

“Do you know how much sugar is in ketchup?” Nora asks. “You might as well call chocolate a vegetable because it was originally made from a bean.”

Casey rests her foot on top of Derek’s, purposefully, then wiggles her toes.

Edwin perks up. “Chocolate’s made from a bean?” He takes a small notebook out from his back pocket and flips it open, taking a pen out from behind his ear. “Interesting,” he murmurs, and scribbles something down.

Derek narrows his eyes at Casey.

She raises an eyebrow at him, daring him to make something of it. She can feel the heat of his foot against her own.

“The cocoa bean,” George says.

Nora scoffs. “Don’t make it a vegetable.”

“It also doesn’t make ketchup _not_ a vegetable, because tomatoes definitely are.”

“One of my teachers said that tomatoes are actually a fruit,” Lizzie pipes up.

“They would,” George mutters.

Derek runs a toe along the instep of her foot, and Casey smothers a giggle. Derek grins at her from across the table.

“Well, somebody’s in a better mood,” Nora says mildly, and Casey drops her foot back to the ground again, trying not to blush.

—

It takes forever for dishes to get done, and then Nora suggests a movie night, and before Casey knows it they’re all bundled up on the couch, watching the opening of the latest Narnia movie. Derek’s in his normal chair and Casey’s on the far end of the sofa, sharing a blanket with Marti and sipping a mug of hot chocolate.

Casey spends most of the movie trying not to look too much in Derek’s direction. It’s harder than she thought it would be.

The normal bedtime rush bustles into action after the credits roll, and Casey lingers downstairs and does homework she can barely concentrate on until the house quiets down and she sees Derek start to head up the stairs. She puts her books away in her bag and catches his eye as she follows him up the stairs.

“Hey. In here,” Derek says, glancing down the hallway and back at the stairs before he pushes the door to his room open, pulling her through after him. It’s all very secret agent-y, and looks way weirder than if Derek had just pushed her into his room directly, arguing with her like normal.

He closes the door behind them, and turns toward her, then pauses.

And then it doesn’t feel easy anymore, like it had when they were playing footsie under the dinner table downstairs, or even when they were watching the movie together with the family. It feels awkward again, that smothering sense of weirdness thick in the air.

Casey shifts her weight to her other foot.

“Pop a squat, Case,” he says, and indicates his bed.

She makes herself respond. “Gross, Derek.”

“Oh, so sorry, princess.” Derek sketches an exaggerated bow in her direction, rolling his hands mockingly. “Forsooth take a seat.”

Casey rolls her eyes, but sits anyway.

She dimly notices that Derek’s bed is made. She’s pretty sure Derek’s bed wasn’t made earlier, when she’d walked past his open door after school. Which means - he’d made his bed, sometime before dinner.

For her.

For her to be in his room, now.

He’d made his bed for her.

She’s still processing this rather shocking piece of information when Derek drops the act and sits down next to her. He clears his throat.

“What?”

“So I’ve been thinking,” he says, then coughs, like he’s nervous.

What on earth would make a guy like Derek _nervous_?

“…What?” she asks again, a little more cautiously.

“So we were talking earlier, right, and then I was thinking about it during the movie, and thought that we’re not - um.” He takes a deep breath in. “We’re not even.”

It’s not what Casey thought he was going to say.

“We’re not _even_? What does that mean?”

“Such suspicion,” he chides, which is total crap, and he knows it.

“What does _even_ mean, Derek?”

“And here I thought you were the smart one out of the two of us.”

Casey tries to keep her voice quiet. Why is Derek always like this!? “We are so even! I don’t owe you anything, and you know it.”

“I’m not saying you owe me,” Derek says, sounding careful again. “I’m saying _I_ owe _you_.”

She narrows her eyes.

“Really?”

“Really.”

“Alright,” she says, reluctantly. “I’ll bite. What do you owe me for?”

“You know when we were… you know. In the Prince.”

Casey feels herself turn red. She’s hyper-aware of Derek’s weight next to her, making the mattress dip in his direction. “Shut up, Derek.“

“And you know how I…” Derek continues, talking over her. “At the end.”

“Seriously, we don’t have to -”

“Kablooey,” Derek says helpfully, and then mimes something like a nuclear explosion.

 _God_.

“Kablooey?” she repeats faintly.

“Kablooey,” Derek agrees, and clears his throat. “The way I figure is that - is that I owe you one. And then we’ll be, um. Even again.”

“You owe me one?”

“I owe you _one_ ,” Derek repeats, stressing the word with a funny edge, like he’s waiting for her to get something.

He owes her…

Oh. _Oh_.

Casey stands up fast, hitting Derek with her arm on her the way up. “Uh,” she says.

“C’mon, Case,” Derek says, and tugs at her elbow. Casey plops inelegantly back down next to him, lying on her back, and looks up at the ceiling of his bedroom.

“Is this your idea of a joke?”

“No.”

“So you seriously want to…” She can’t even make herself say it.

Derek swallows. “Yeah. I want to.” His voice goes strange, oddly thick, when he says the words. A nervous, giddy, unreal sort of hilarity starts to build up inside of her.

“Have you ever done… _that_ … before?” she asks. She kind of guesses he has, with the way he talks and the girls he scores, but maybe that’s just talk.

Derek hesitates. “Sort of.”

“Sort of? What does sort of mean?”

“It means I’ve… you know, done the third base thing once but we… didn’t really do much.”

She wonders, distantly, through the buzzing in her head, who that happened with. Sally? Some other girl?

Derek reclines next to her, propped up on an elbow, facing her. Their legs are touching. “What about you?”

“What about me?”

“You know.” He sticks out his chin defiantly. He’s so _close_ to her. Casey starts to breathe faster.

“Not really, I guess.”

“What does that mean?”

She squirms. “It means not exactly, stupid.”

“What does _that_ mean?”

“It means - I mean, I’ve done some…” She trails off. “I haven’t done that.”

Derek leans in, over her, so their noses are touching. “Do you want to?”

“Yes,” she whispers, the word out of her mouth before she really thinks about what she’s agreeing to. Her brain catches up with the rest of her a second later, and a wave of horrifying embarrassment follows fast. Casey feels like she’s about to start giggling or probably die out of sheer nervousness, because she can’t believe she just agreed to… what, exactly? Let Derek try to get her off? How are they actually discussing this as a real thing? What does that even mean??

Derek breathes in sharply at her answer, and it occurs to Casey that he’d probably been expecting her to say no.

“I don’t -“ she starts to say.

“What do you -“ Derek says, at the same time.

They both pause, and then Derek cracks a funny sort of grin.

Casey turns to hide her face in his shoulder. “Oh my god, this is so embarrassing.”

“Tell me about it.”

Derek touches her bare arm, hesitates, then kisses her.

Casey tries to remember how great it’s been to make out with Derek, how nice it is but also how _understandable_ it mostly is, in a surreal, she-really-shouldn’t-be-kissing-her-stepbrother sort of way. But all she can think about instead is how she just agreed to probably let Derek stick a hand down her pants, and god, she can’t stop thinking about it now!

But Casey can’t make herself take the words back. It would be dumb to turn him down at this point anyway, right? She can just imagine him teasing her about wimping out, and NO WAY is she ever going to let Derek get the upper hand on her for something like this. Right.

Because it’s like, sure, she’s masturbated. She’s not a dummy; she knows she’s going on. But she’s also not particularly good at it, a fact which she’s always found embarrassing and not a little bit annoying - it’s freaking _masturbation_. Isn’t everybody in the world supposed to be a natural at getting off? Casey’s a go-getter, after all. Casey’s the type of girl who comes home with straight As and Gets Stuff Done, the type of girl who masters anything she puts her mind to. Masturbation ought to be a cinch.

But most of the time when she tries it she feels like she’s randomly wiggling her fingers around between her legs. She knows where her clitoris is, and she likes how it feels when she sticks her fingers inside of herself, but mostly she just manages to give herself a nice, warm, pulsing sort of feeling that she can’t seem to do much with.

The couple times she’d managed to come have almost felt like an accident, an orgasm-y by-product of something else she happened to have been doing while her fingers were hanging out near her vagina. The only thing Casey knows is that it’s better when she’s turned on beforehand, swollen and sticky, which is kind of gross but also kind of hot.

The first time she’d orgasmed had been a revelation; she remembers lying in her bed, panting and staring up into the darkness, and thinking, _oh. So that’s why guys do it_.

Derek shifts his weight, crawling partially on top of her, continuing to kiss her.

And she can feel Derek’s erection again, like that time they’d made out in the Prince, against her leg. He’s not pressing it up against her, though - it’s just sort of… there, heavy against her thigh. Derek’s kissing is turning dirtier, messier, and Casey’s nervousness begins to fade into a heady, breathless rush, sort of like she’d felt when the two of them were drunk (only, like, the 100% sober, making out-only version of that feeling).

She doesn’t understand why this is so _good_. Her reaction to Derek is crazy, it’s off the charts. She doesn’t understand it at ALL.

She shoves Derek’s shoulders and says, “Hey. Take off your shirt.”

Derek complies almost embarrassingly fast, peeling his t-shirt off over the top of his head, like he’d been waiting for her to ask him to strip this entire time.

Casey stops him from kissing her again, though.

“What?”

“Let’s, um…” Casey tries to push Derek sideways, over next to her. God, why can’t he just read her mind or something and magically do what she wants him to do?

A dim light of understanding dawns in Derek’s eyes after a moment, and he flops down next to her then, onto his back. He pulls her waist along with him to roll her over, on top of him.

Casey ends up straddling his hips, looking down at him. She wiggles a bit on her knees, trying to get comfortable, and Derek’s eyes go funny when she does that. He grabs her hips - to stop her or help her, Casey’s not sure.

She’s the one to kiss Derek this time, leaning down to press her mouth against his. She puts her hands on either side of Derek’s head, bracing her body above his. His chest is pale in the dark room underneath her, thin and wiry but also pretty strong looking.

Derek puts his hands on her hips, and nudges her shirt up an inch or two. Derek’s hand moves up under her shirt a bit more, brushing her stomach. His hand hovers in the vicinity of her bellybutton, drifting against her skin. She’s intensely aware of her the waistband of her jeans, an inch or two below where his fingers are.

“You want to lose your shirt, too?” he asks, kind of flippantly, his tone at odds with the way he’s looking at her.

“Why, so we can match?”

“Um, sure. ‘Cause of that.”

She sits back on her heels to strip her shirt off over her head, because at least this part of what they’ll potentially be doing she understands. She’s done this part before; she knows she likes it.

Derek’s hands drift up to her chest, and trace along the underwire in her bra, underneath her breasts. Casey shivers.

“Cold?”

“A little,” she says.

Derek laughs under his breath, and Casey kisses him again, to shut him up. This is the best way she’s ever found to shut Derek up, bar none. She should have been doing this years ago! It would have saved both of them so much trouble.

Derek’s palms slide up over her breasts after a while, and Casey lets him feel his way around, squeezing and kneading enthusiastically. Casey doesn’t really get a ton out of it, but occasionally his fingers slide past her nipples in a way that makes her breath catch. Derek, at least, seems to be super into it.

“You have great boobs,” Derek says after a while, his voice absolutely serious.

“Thanks,” she says, barely managing to turn the word from a question into a statement at the last moment.

Derek lunges then, wrapping his arms around her whole body like he’s tackling her, and the next thing Casey knows her back is hitting the mattress and Derek’s weight is on top of her again.

They make out for a while longer after that, but Derek doesn’t make any move to take her bra off or push a strap down, like Casey was half-guessing he might. After a bit, though, he rubs his thumbs over her nipples instead of just going to town on her whole breast; Casey gasps the feeling helplessly into Derek’s mouth, a hollow ache thrumming wetly between her legs.

It seems to turn Derek on even more, her response to him, his breathing going irregular and fast. He shifts his weight off her, lying down next to her instead of right on top of her, and reaches down to undo the button of her jeans.

Casey doesn’t even think about it, she just lifts her hips and helps him take her jeans the rest of the way off, yanking the zipper down, wiggling when the fabric sticks to her thighs. Her underwear is white, pale in the darkness, and she thinks it probably looks nice, mostly matching her blush pink bra.

She finishes kicking off her jeans right as it occurs to her that she is lying on Derek’s bed.

In her bra and underwear.

A shiver like fear or anticipation crawls down her skin, raising goosebumps on her bare legs. She rubs her thighs together and licks her lips. She feels on edge like this, exposed and turned on in equal measure.

She tenses, waiting for… something… when Derek starts kissing her again, like nothing’s changed despite the fact that she’s, like, 90% naked now, the palm of his hand grasping the jut of her hip.

After a minute, Derek slides his hand down the front of her underwear, and he pauses when he reaches her crotch, two fingers pressed there, hesitating awkwardly.

And oh _god_. It occurs to her for the first time that he can probably feel that she’s wet, which is a thought so embarrassing that Casey wants to sink into the bed and disappear on the spot. She’s, like, _pulsing_ , and she can feel the slickness between her own legs, sort of like she’s peed herself a little bit, and it’s probably made her underwear all disgusting and sticky. It’s kind of horrifying that Derek knows this about her now.

“You gonna do it?” she goads, to hide her nerves. She can feel his fingers, motionless against the cotton of her underwear. What’s his deal anyway? She thought all teenage boys lived for this moment, getting a hand down some girl’s pants. The longer her waits the more on-edge it makes her, like she’s doing something wrong, like he’s about to pull back and start laughing, like maybe this was all just some big, awful joke this entire time.

And she knows that’s not really true, but the fear is there for one quick, stomach-clenching moment. She feels crazy vulnerable like this. It’s hard _not_ to be nervous.

Derek takes a deep breath in.

“You have to tell me what you like,” he says then, and Casey almost wants to scream with frustration. Why doesn’t he just KNOW, why is Derek making this so DIFFICULT. “You gotta promise to tell me, okay?”

“Fine,” she snaps. “Fine, whatever, but you can’t just…”

Derek moves his fingers against her, rubbing in an awkward little circle, and Casey snaps her mouth shut. 

He’s not trying to get under her underwear, just… rubbing on top of the cotton, and occasionally bumping up against her clitoris, making the muscles of her stomach clench whenever he does. It feels nice, but also a little weird, because she never just rubs the fabric of her underwear against herself.

Derek slides a leg over one of her thighs then, so his knee is between her, pinning her legs apart, and he buries his face further into her neck, his fingers moving in semi-circles the whole time. His breath is hot against her neck, panting.

He does this a couple more times, and his fingers pause.

“You know, you can…” She can’t make herself finish the thought out loud. She reaches for Derek’s hand before thinking it through.

She tangles her fingers up in his and yanks his hand up and under, shoving his fingers underneath her underwear proper and against herself, instead of the weird over-the-panties thing he’d been doing.

They both freeze.

Her hand is still there, next to his, his fingers tangled up with hers like they’re holding hands or something, except both of their hands also pressed against her vagina, slipping against the wetness there, their palms resting against her pubic hair, and Casey can _feel_ his fingers against hers, in more than one way, with shocking clarity.

Derek’s fingers twitch, and Casey jumps.

“Oh,” she says, and almost doesn’t recognize her own voice.

“You’re so wet,” Derek whispers, and Casey blushes hot, feeling obscurely like he’s accusing her of something.

Should she untangle her fingers from his? Would removing her hand just draw more attention to the weird position they’d both ended up in, or should she…

Derek moves his fingers again in that same circular motion, and Casey gasps involuntarily, her fingers drawn along with his.

“Oh my god,” Derek says, low. He’s turned his head a bit to look down at both of their hands, stuck into her underwear like some sort of multi-legged hand-spider thing.

She shifts her fingers a little, trying to get out of this awkward holding-hands-next-to-her-vagina position they’ve found themselves in, and hits her own clit accidentally. She can’t swallow the sound that escapes her throat fast enough, and Derek shifts to look at her face.

“Fuck,” he says. “Fuck.”

What the hell. “I like this,” she says, before she loses her nerve, and grasps his hand to rub it against herself in the quick back-and-forth she knows she likes the most. She can feel herself touching her own clit, the folds of sensitive skin, Derek’s fingers gliding along next with hers, and she gasps with shock at the doubled-up feeling. 

Derek picks up the motion quickly, following her lead. She closes her eyes, unable to stand the way he’s watching her, and slowly draws her hand back a little, so her palm is resting on her lower stomach. She can feel the hot slickness still coating her own fingers.

“Does that… is this okay?” Derek’s voice is hoarse, close to her ear. He sounds older to her like this, with her eyes closed.

“Yeah. Yes.”

Derek pauses, and he shifts his knee up a little higher between her legs, then, slowly, slips a single finger into her. He pants harshly into her neck, and Casey’s mind goes crazy, because this is _actually happening_ , oh god!

And it feels different than when she puts her own fingers inside herself, when all she can think about is how squishy and weird and kind of bumpy her own vagina feels like, and without that immediate feedback the only thing that’s left is this odd but interesting sensation of something being inside of her.

Derek hoists himself up on one elbow then and kisses her hard.

He starts moving his one finger in and out of her as he kisses her, and Derek’s tongue in her mouth is overwhelming like this. She’s never realized how _sexual_ it is to kiss somebody until this moment, when Derek has one finger hooked inside of her body and he’s kissing her like he’s going out of his mind at the same time.

She wonders if he’d ever thought about this before, when they made out in the Prince or that night he got a hard-on when they were playing Twister. The idea of him wanting this, of him thinking about her _like this_ , maybe even before this whole bonkers thing between them started, makes something hot and dark turn over deep inside of her.

“Did you ever think about this?” she half-pants, unable to stop herself from asking, her voice weird and disjointed.

“Yes,” he gasps, and whoa, there is no way he meant to say that so fast. The word escapes from him like some sort of confession he’d kept inside, like he’s not even aware of how he sounds when he says it.

“Oh god,” she says, and buries her face in his neck. She can feel his pulse there, fast and erratic.

Derek’s thumb starts to worry her clit again, in a rough imitation of what she showed him to do, and Casey is drowning in how good this feels, even how clumsy his fingers are is doing it for her. Her whole body is alive with forces she barely comprehends.

And she’s trying so hard not to make a bunch of humiliating noises, biting her lip to keep it in. Moans keep catching in her throat. Her body is moving of its own volition now, hips tilting off the bed, her eyelids fluttering back and forth between open and closed.

Casey wishes, desperately, that she knew what to do with her hands. What do people do with their hands while this happens!? Her left arm is trapped underneath Derek’s body and the other is scrambling at her right side, plucking fitfully at the comforter. She finally yanks the arm wedged underneath Derek’s torso out and wraps it around Derek’s shoulders instead, winding the two of them closer together.

Derek straight-up _groans_ at that. Casey can feel herself getting even wetter at the sound, can hear the faint squelching of Derek’s fingers as they move against her, and god, this is the most embarrassing thing that’s ever happened to her, _ever_ , and she doesn’t care AT ALL. Everything is overwhelming; shockingly intense and weird at the same time.

“C’mon, Casey, c’mon, please,” Derek says, in her ear, panting the words, almost begging, and somehow that’s the thing that does it. Casey tightens her fist in Derek’s hair and everything that was wound up inside of her breaks and spills open.

The next thing she knows Derek is fumbling at her waist, and then there’s a hand that smells strangely like herself clamped over her mouth. Casey shudders while Derek mutters something like “quiet, you have to be quiet,” his breath fast and wild against her neck.

Derek drops his hand from her mouth a second later, taking the sharp, bitter smell of his fingers with it, and Casey stares at the ceiling of Derek’s room, dazed.

Derek flips himself onto his back next to her then, rolling away from her a bit, and his hands scramble at his zipper. Casey turns her head to look as he pulls his dick out faster than Casey thought was possible. She only has a brief glimpse of something sticking out from Derek’s body before Derek’s drags his fist up and down his dick once, twice, and comes hard across his stomach. His eyes roll back in his head, groaning something that Casey thinks, with dim shock, might be her own name.

Casey’s never actually _seen_ a penis before. There’s a sort of white goo splattered in thin ropes up from Derek’s belly button to his ribs, and she can already see his dick softening in his grasp. She’s never seen anything like this at all before. It’s way disgusting, but it’s also… _not_ , in this way makes Casey’s stomach twist up hotly.

“Sorry,” Derek pants a second later, letting go of his dick to grab the t-shirt he’d been wearing earlier from the side of the bed, and wipes the come off his stomach and dabs a last bit of it off the top of his penis. Casey watches, wide-eyed. “Sorry. Sorry. I just…” He doesn’t seem to know how to finish that sentence.

Derek shifts his pants and underwear, pulling his dick back inside the slit in his boxers, and glances back over at her. His face and ears are pink.

“Sorry,” he says again.

She swallows, and makes herself respond. “For what?”

“For, you know,” Derek gestures at himself, making a quick half-gesture like jerking himself off, with that odd look of embarrassment again.

Casey clears her throat, trying not to blush as well. “Seemed fair to me.”

Derek huffs a short laugh. “Right.”

Casey sits up and hunts around for her t-shirt, which she finds bunched up underneath a pillow near the top of the bed. She pulls it on, tugging it down to cover her bare stomach, and re-adjusts her underwear, trying to ignore her now-sticky thighs.

When she settles back down, Derek leans over and kisses her, once, gently.

“What was that for?” she asks as he pulls back.

“That was because _this_ ,” Derek gestures around both of them, encompassing the bed and the room in a big, circular motion, “was _awesome_.”

Casey laughs, unable to help herself. 

“It was, wasn’t it?”

“The best,” Derek agrees, grinning now, looking more like himself.

“The best of the best.”

“We should challenge people to duels doing this,” Derek suggests, starting to sound sort of giddy.

Casey wrinkles up her nose. “Eew. Gross, no.”

“But we would win. We would kill the competition, Case. I know how you like being the best at things.”

“I do like winning,” Casey agrees. “But also, no way. Never in a million years, Derek.”

Derek grabs her waist and pulls him into his body, tucking her head underneath his chin. “I guess we’ll just have to hone our skills in private, then.”

Something flutters deep in Casey’s chest at that. “Yeah?” she says, and her voice is more quiet than she means it to be.

Derek looks down at her. “I think so,” he says, his voice gone strangely serious as well.

They lay there, quietly, together, Derek’s hand idly stroking her side, as the night falls around them.

—

It starts, as most things do, with being Derek being a total jerk.

“No way!” Casey says, stomping her food. “You know I have the Prince on Saturday, Derek.”

“Yeah, but I,” Derek drawls the word out lazily, “have a _date_.”

Casey throws up her hands. “Nobody cares about your dates! How many times do I have to say that!”

Derek shrugs.

“You should let Derek go on his date,” George says, from where he’s sitting with Nora at the kitchen table, both of them going over the budget for the month.

“Oh, so now you’re on Derek’s side?” Casey asks, putting her hands on her hips.

George holds up his hands. “I never said anything like that. I’m just saying, you guys have traded days before, right?”

“George has a point,” Nora says, using her I’m-your-mother-and-what-I’m-suggesting-is-completely-reasonable voice.

Casey narrows her eyes, then turns on Derek.

“Do you like this girl?” she asks.

“What?”

“This girl you’re taking out on a date. Do you even like her?”

“What’s it to you?”

Casey crosses her arms and glares until Derek relents, shrugging.

“She’s…” Derek pauses, searching for words. “This girl is… something else.”

“Something else?” Marti repeats, tugging on Derek’s sleeve so he looks down at her.

“Something else, Smarti,” Derek agrees, that warm, open note entering his voice, like he gets when he’s talking to Marti or when it’s late at night and darkness wraps around Casey and Derek, like they’re the only two people still awake in the entire world, whispering to each other as the house settles around them.

“Fine,” Casey says, and sniffs loudly, just to make it very clear to everybody what her feelings on the matter are. “You can have the car if you drop me off at the mall first. _And_ pick me up again afterward.”

“You drive a hard bargain, Case.”

“Deal or no deal?”

“Deal,” Derek says promptly, and holds out his hand.

Derek’s palm is warm against her own, and he squeezes her fingers as they shake on it.

He winks at her as they release hands.

“Deal,” Casey agrees, and smiles, vowing to make him pay for the popcorn on their date later.

**Notes for the Chapter:**

> I can't believe we're here! Thank you so much to everybody who left kudos, messages, comments, or bookmarked this story, and a final THANK YOU to my three beta readers: jaegermighty, htbthomas, and ghostcat. You all are the best. <3
> 
> Also, if you enjoyed this story and would like to share it, please consider reblogging [this post on tumblr](http://blithers.tumblr.com/post/148324440428/a-kind-of-merry-war-37185-words-by-blithers)!


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